TIME

What is TIME?

The TIME protocol is a simple network protocol used for retrieving the current time from a remote server. It allows clients to synchronize their clocks by receiving a timestamp from a server.

Why is TIME useful?

  • Provides an easy and lightweight way to synchronize system clocks.

  • Essential for logging and time-based functions in computer systems.

  • Often used in legacy systems or where precision time synchronization (like NTP) is not required.

  • Helps in the alignment of time across devices on a network.

How it works?

  • A client sends a request to a TIME server.

  • The server responds with the current time in a standardized format.

  • The client adjusts its system clock based on the received timestamp.

  • The protocol operates over TCP, using port 37 for communication.

Where is TIME used?

  • Often used in older systems or devices that need simple time synchronization.

  • Primarily found in legacy computing systems or embedded devices.

  • Used where high precision (like NTP) is not required, and basic time updates are sufficient.

Which OSI layer does this protocol belong to?

  • The TIME protocol operates at the Application Layer (Layer 7) of the OSI model.

  • It relies on the Transport Layer for communication, typically using TCP.

Is TIME Windows specific?

  • No, TIME is not Windows-specific.

  • It is supported on various operating systems, including UNIX, Linux, and even some embedded systems.

Is TIME Linux specific?

  • No, TIME is not Linux-specific.

  • It can be implemented on any operating system that supports TCP/IP and can use port 37 for communication.

Which Transport Protocol is used by TIME?

  • TIME typically uses TCP (Transmission Control Protocol) for communication.

  • It ensures reliable, ordered transmission of time data from the server to the client.

Which Port is used by TIME?

  • The TIME protocol operates over TCP port 37 for communication between the client and server.

Is TIME using Client-server model?

  • Yes, the TIME protocol follows the client-server model.

  • The client sends a request to the server, which then responds with the current time.

Topics in this section,

  • In this section, you are going to learn

  • Terminology

  • Version Info

RFC details

S.No

TIME Version

core Idea/ Contribution

RFC Details

1

TIME Protocol v1

Defines a simple protocol for retrieving the current time as a 32-bit unsigned integer representing seconds since

RFC 868

00:00:00 UTC on January 1, 1900. Supports both TCP and UDP over port 37.

TIME protocol over TCP using IPv4 on interface enp0s8

  • Step-1: Assign IPv4 Addresses for two VM’s.

    test:~$sudo ip addr add 192.168.200.1/24 dev enp0s8
test:~$sudo ip link set enp0s8 up
test:~$sudo ip addr add 192.168.200.2/24 dev enp0s8
test:~$sudo ip link set enp0s8 up

  • Step-2: Create TIME Service Configs.

    test:~$sudo nano /etc/xinetd.d/time-tcp

  • Step-3: Enable and Start xinetd.

    test:~$sudo systemctl enable xinetd
test:~$sudo systemctl restart xinetd

  • Step-4: Verify TIME service is listening.

    test:~$sudo netstat -tulnp | grep ":37"

  • Step-5: Test from Another VM.

    test:~$rdate -p 192.168.200.1
You should see the current time printed

  • Step-6: Wireshark Capture.

    :download:Download wireshark capture <TIME/time_ipv4_tcp.pcapng>

TIME protocol over TCP using IPv6 on interface enp0s8

  • Step-1: Assign IPv6 Addresses for two VM’s.

    test:~$sudo ip addr add 2001:db8:abcd:1/64 dev enp0s8
test:~$sudo ip link set enp0s8 up
test:~$sudo ip addr add 2001:db8:abcd:2/64 dev enp0s8
test:~$sudo ip link set enp0s8 up

  • Step-2: Install Required Packages.

    test:~$sudo apt update
test:~$sudo apt install -y xinetd rdate net-tools

  • Step-3: Create TIME Service Configs (IPv6).

    test:~$sudo nano /etc/xinetd.d/time-stream

  • Step-4: Enable and Start xinetd.

    test:~$sudo systemctl enable xinetd
test:~$sudo systemctl restart xinetd

  • Step-5: Verify TIME service is listening on IPv6.

    test:~$sudo ss -tln6 | grep :37    # TCP

  • Step-6: Test from Another IPv6 VM.

    test:~$rdate -6 -p 2001:db8:abcd::1
  • Step-6: Wireshark Capture.

    :download:Download wireshark capture <TIME/time_ipv6_tcp.pcapng>

Client Request Packet

S.No

Protocol Packet

Description

Size(Bytes)

1

Client Request Packet

The client sends an empty request to the server on port 37 (TCP or UDP).

0 (no payload)

Application Data

No payload is sent; the client simply initiates a connection to port 37.

0

Total Packet Size

No application-layer data; only transport and IP headers are used.

0 Bytes

Server Response Packet

S.No

Protocol Packet

Description

Size(Bytes)

2

Server Response Packet

The server responds with a 32-bit unsigned integer representing the number of seconds since

4

00:00:00 UTC on January 1, 1900.

Timestamp

A 32-bit unsigned integer representing seconds since 00:00:00 UTC on Jan 1, 1900

4

Total Packet Size

The entire TIME protocol response consists of this single field.

4 Bytes

Use Case

S.No

Use Case

Description

1

Legacy System Time Sync

Used in older operating systems and network devices that support only basic time protocols.

2

Minimal Embedded Systems

Ideal for microcontrollers or embedded devices with limited memory and processing power.

3

Boot-Time Clock Initialization

Helps systems without a real-time clock (RTC) to set the correct time during startup.

4

Network Time Testing

Useful for verifying time server availability and basic time accuracy in test environments.

5

Fallback Time Source

Acts as a backup when NTP or SNTP services are unavailable or unsupported.

6

Firewall-Friendly Time Sync

Easier to allow through firewalls due to its simple use of TCP/UDP port 37.

7

Educational Demonstrations

Used in labs and classrooms to demonstrate basic client-server time exchange.

8

Simple IoT Devices

Suitable for Internet of Things devices that need basic time stamping.

9

Low-Bandwidth Environments

Efficient in networks with limited bandwidth due to its small 4-byte response.

10

Custom Time Clients

Developers can build lightweight time clients for specific applications or platforms.

11

Historical Protocol Compatibility

Maintains compatibility with older systems or software that still rely on RFC 868.

12

Offline Time Sync Testing

Can be used in isolated networks or virtual labs to simulate time synchronization.

Basic Features

S.No

Feature

Description

1

Simplicity

TIME protocol is extremely simple, consisting of a single 4-byte response from the server.

2

Lightweight Communication

Requires minimal bandwidth and processing, making it ideal for low-resource environments.

3

TCP and UDP Support

Can operate over both TCP and UDP transport protocols on port 37.

4

Fixed Epoch

Uses a fixed epoch starting from January 1, 1900, unlike Unix time which starts from 1970.

5

Stateless Server

The server does not maintain any session or state; it simply responds with the current time.

6

Firewall-Friendly

Operates on a single well-known port (37), making it easier to configure in firewalled environments.

7

Cross-Platform Compatibility

Can be implemented on any system that supports basic TCP/UDP networking.

8

No Authentication Required

Does not require credentials or encryption, simplifying implementation (though less secure).

9

Legacy System Support

Still supported in some older operating systems and embedded devices.

10

Quick Time Retrieval

Provides a fast and efficient way to retrieve the current time from a remote server.

Simplicity - Testcases

Simplicity

S.No

Test Case

Description

Expected Result

1

Default Configuration

Start TIME service with default settings

Service starts successfully

2

Minimal Setup

Configure TIME with minimal parameters

Time sync works

3

One-Command Start

Start TIME with a single command

Service starts and syncs

4

Simple CLI Help

Run –help command

Clear and concise help output

5

Simple Config File

Use a basic config file

TIME reads and applies settings

6

Human-Readable Logs

Check log format

Logs are easy to understand

7

Clear Error Messages

Trigger a config error

Error message is descriptive

8

Simple Time Format

Output time in standard format

Time is readable (e.g., ISO 8601)

9

Easy Installation

Install TIME on Linux

Installation completes with one command

10

Easy Uninstallation

Uninstall TIME

TIME removed cleanly

11

Simple Update

Update TIME version

Update completes without issues

12

Minimal Dependencies

Check required packages

Only essential dependencies used

13

Simple API Call

Make a time request via API

Response is quick and readable

14

Simple JSON Output

Request time in JSON

Output is clean and structured

15

Simple Integration

Integrate TIME with app

Integration succeeds with minimal code

16

Simple Sync Check

Check sync status

Output is clear (e.g., “Synced”)

17

Simple Restart

Restart TIME service

Service restarts without errors

18

Simple Port Usage

Use default port

TIME listens on standard port

19

Simple Firewall Rule

Allow TIME through firewall

Rule added with one command

20

Simple Time Drift Correction

Detect and correct drift

Drift corrected automatically

21

Simple Client Setup

Configure TIME client

Client syncs with server

22

Simple Server Setup

Configure TIME server

Server responds to requests

23

Simple Debug Mode

Enable debug mode

Extra logs appear clearly

24

Simple Status Command

Run status check

Output is readable

25

Simple Time Zone Handling

Set time zone

TIME respects system time zone

26

Simple UTC Output

Output time in UTC

UTC time displayed

27

Simple Local Time Output

Output local time

Local time displayed

28

Simple Sync Interval

Set sync interval

TIME syncs at set interval

29

Simple Retry Logic

Handle failed sync

Retry occurs automatically

30

Simple Logging Toggle

Enable/disable logging

Logging toggled easily

31

Simple Version Check

Check TIME version

Version displayed clearly

32

Simple Help Docs

Access documentation

Docs are concise and clear

33

Simple GUI (if available)

Use GUI interface

GUI is intuitive

34

Simple Mobile Support

Use TIME on mobile

App syncs time easily

35

Simple Cross-Platform Support

Run on Windows/Linux/Mac

TIME works consistently

36

Simple Config Validation

Validate config file

Errors shown clearly

37

Simple Backup

Backup TIME settings

Backup created easily

38

Simple Restore

Restore TIME settings

Settings restored correctly

39

Simple Sync Log

View sync history

Log is easy to read

40

Simple Time Accuracy Display

Show sync accuracy

Accuracy shown in ms

41

Simple Network Setup

Use TIME over LAN

Sync works without extra setup

42

Simple IPv6 Support

Use TIME with IPv6

Sync works over IPv6

43

Simple IPv4 Support

Use TIME with IPv4

Sync works over IPv4

44

Simple Error Recovery

Recover from crash

TIME restarts and resumes

45

Simple Notification

Notify on sync failure

Alert is shown or logged

46

Simple Time Source Switch

Switch time source

TIME adapts automatically

47

Simple Offline Mode

Run in offline mode

TIME uses cached time

48

Simple Sync Verification

Verify time sync

Output confirms sync

49

Simple User Permissions

Run as non-root user

TIME works with limited permissions

50

Simple Security Settings

Enable basic security

TIME uses secure defaults

Ligthweight Communication - Testcases

Lightweight Communication

S.No

Test Case

Description

Expected Result

1

Send Basic Message

Send a simple text message

Message is delivered successfully

2

Receive Basic Message

Receive a simple text message

Message is received and displayed

3

Timestamp Accuracy

Verify timestamp on sent message

Timestamp matches system time

4

Timestamp Sync

Verify timestamp sync between sender and receiver

Timestamps are consistent

5

Message Acknowledgement

Check if ACK is sent after message received

ACK is received by sender

6

Message Retry on Failure

Simulate network failure

Message is retried automatically

7

Message Order

Send multiple messages in sequence

Messages are received in order

8

Duplicate Message Handling

Send same message twice

Duplicate is detected and ignored

9

Message Size Limit

Send message at max allowed size

Message is accepted and delivered

10

Exceed Message Size

Send message exceeding size limit

Error is returned

11

Empty Message

Send an empty message

Error or warning is shown

12

Special Characters

Send message with special characters

Message is delivered correctly

13

Unicode Support

Send message in non-English script

Message is displayed correctly

14

Message Encryption

Send encrypted message

Message is decrypted correctly

15

Message Integrity

Tamper with message in transit

Integrity check fails

16

Delayed Delivery

Simulate network delay

Message is eventually delivered

17

Offline Storage

Send message while receiver is offline

Message is stored and delivered later

18

Message Expiry

Set expiry time on message

Message is deleted after expiry

19

Priority Messaging

Send high-priority message

Message is delivered before others

20

Low Bandwidth Mode

Simulate low bandwidth

Message is compressed and delivered

21

Connection Timeout

Simulate timeout during send

Timeout error is shown

22

Reconnection Handling

Disconnect and reconnect

Messages resume after reconnect

23

Multi-Device Sync

Send from one device, receive on another

Message syncs across devices

24

Message Queueing

Queue messages when offline

Messages are sent when online

25

Message Logging

Log all sent/received messages

Logs are accurate and complete

26

Message Deletion

Delete a sent message

Message is removed from receiver

27

Message Edit

Edit a sent message

Updated message is shown

28

Message Read Receipt

Enable read receipts

Sender sees read status

29

Message Delivery Receipt

Enable delivery receipts

Sender sees delivery status

30

Group Messaging

Send message to multiple recipients

All recipients receive message

31

Broadcast Messaging

Send broadcast message

All users receive message

32

Message Compression

Compress large message

Message is compressed and delivered

33

Message Fragmentation

Break large message into parts

All parts are reassembled correctly

34

Protocol Version Compatibility

Use different protocol versions

Communication still works

35

Invalid Protocol Header

Send message with invalid header

Error is returned

36

Unauthorized Sender

Send message from unauthorized user

Message is rejected

37

Session Timeout

Let session expire

New session is required

38

Session Reuse

Reuse existing session

Session is valid and reused

39

Time Drift Detection

Simulate clock drift

Drift is detected and corrected

40

Time Sync Request

Request time sync from server

Time is updated correctly

41

Time Zone Handling

Send message across time zones

Time is displayed in local time

42

Daylight Saving Adjustment

Send message during DST change

Time is adjusted correctly

43

Message Format Validation

Send malformed message

Error is returned

44

Protocol Handshake

Initiate handshake

Handshake completes successfully

45

Secure Channel Establishment

Establish secure channel

Channel is encrypted

46

Message Replay Attack

Replay old message

Replay is detected and blocked

47

Load Testing

Send 1000 messages rapidly

System handles load without failure

48

Stress Test

Simulate high traffic

System remains stable

49

Latency Measurement

Measure message round-trip time

Latency is within acceptable range

50

Resource Usage

Monitor CPU/memory during messaging

Usage is within limits

TCP and UDP Support - Testcases

TCP and UDP Support

S.No

Test Case

Description

Expected Result

1

TCP Connection Establishment

Connect to TIME server over TCP

Connection established

2

UDP Packet Send

Send TIME request over UDP

Server responds with time

3

TCP Time Format

Validate time format over TCP

32-bit unsigned integer

4

UDP Time Format

Validate time format over UDP

32-bit unsigned integer

5

TCP Port Listening

Check if server listens on TCP port 37

Port is open

6

UDP Port Listening

Check if server listens on UDP port 37

Port is open

7

TCP Response Time

Measure response time over TCP

< 100ms

8

UDP Response Time

Measure response time over UDP

< 100ms

9

TCP Connection Timeout

Simulate timeout on TCP

Connection times out

10

UDP Packet Loss

Simulate packet loss on UDP

No response or retry

11

TCP Invalid Request

Send malformed TCP request

Server ignores or closes connection

12

UDP Invalid Request

Send malformed UDP packet

Server ignores packet

13

TCP Multiple Clients

Connect multiple clients via TCP

All receive valid time

14

UDP Multiple Clients

Send multiple UDP requests

All receive valid time

15

TCP Server Crash Recovery

Restart server after crash

Server resumes correctly

16

UDP Server Crash Recovery

Restart server after crash

Server resumes correctly

17

TCP Firewall Block

Block TCP port 37

Connection fails

18

UDP Firewall Block

Block UDP port 37

No response

19

TCP IPv6 Support

Connect using IPv6 over TCP

Connection successful

20

UDP IPv6 Support

Connect using IPv6 over UDP

Response received

21

TCP High Latency

Simulate high latency

Time still received

22

UDP High Latency

Simulate high latency

Time still received

23

TCP Packet Sniffing

Capture TCP packet

Time value visible

24

UDP Packet Sniffing

Capture UDP packet

Time value visible

25

TCP Time Accuracy

Compare time with NTP

Within 1 second

26

UDP Time Accuracy

Compare time with NTP

Within 1 second

27

TCP Port Scan Detection

Scan for TCP port 37

Server logs or ignores

28

UDP Port Scan Detection

Scan for UDP port 37

Server logs or ignores

29

TCP Connection Flood

Flood with TCP connections

Server handles or throttles

30

UDP Flood Attack

Flood with UDP packets

Server handles or throttles

31

TCP Keep-Alive

Maintain long TCP connection

Server closes after response

32

UDP Statelessness

Send multiple UDP packets

Server responds to each

33

TCP Logging

Check server logs for TCP

Request logged

34

UDP Logging

Check server logs for UDP

Request logged

35

TCP Authentication

Attempt auth on TCP

Not required

36

UDP Authentication

Attempt auth on UDP

Not required

37

TCP Encryption

Attempt TLS on TCP

Not supported

38

UDP Encryption

Attempt DTLS on UDP

Not supported

39

TCP Time Drift

Check time drift over hours

Drift < 1s/hour

40

UDP Time Drift

Check time drift over hours

Drift < 1s/hour

41

TCP Retry Mechanism

Retry on TCP failure

Time received on retry

42

UDP Retry Mechanism

Retry on UDP timeout

Time received on retry

43

TCP Server Load

Test under high TCP load

Server remains responsive

44

UDP Server Load

Test under high UDP load

Server remains responsive

45

TCP Packet Fragmentation

Send fragmented TCP packets

Server reassembles correctly

46

UDP Packet Fragmentation

Send fragmented UDP packets

Server handles or drops

47

TCP NAT Traversal

Connect from NATed client

Time received

48

UDP NAT Traversal

Send from NATed client

Time received

49

TCP Version Compatibility

Test with various OS TCP stacks

All succeed

50

UDP Version Compatibility

Test with various OS UDP stacks

All succeed

Fixed Epoch - Testcases

Fixed Epoch

S.No

Test Case

Description

Expected Result

1

Validate Epoch Start

Check if time starts from 1900-01-01 00:00:00 GMT

Time = 0

2

Validate Epoch Offset

Compare TIME value with Unix epoch

TIME = UNIX + 2208988800

3

Past Date Before Epoch

Request time before 1900

Not supported or error

4

Epoch Consistency

Restart server and check epoch

Epoch remains fixed

5

Epoch Format

Validate 32-bit unsigned integer format

Correct format

6

Epoch Overflow

Simulate time past 2036

Wraps or handled correctly

7

Epoch Leap Year

Validate leap year handling since 1900

Accurate time

8

Epoch Leap Second

Validate leap second handling

Ignored (as per spec)

9

Epoch Time Drift

Compare with NTP server

Within 1s

10

Epoch Conversion

Convert TIME to human-readable date

Matches expected date

11

Epoch in TCP

Validate epoch in TCP response

Correct

12

Epoch in UDP

Validate epoch in UDP response

Correct

13

Epoch in IPv6

Validate epoch over IPv6

Correct

14

Epoch in IPv4

Validate epoch over IPv4

Correct

15

Epoch in Big Endian

Validate byte order

Big endian

16

Epoch in Little Endian

Send little endian

Server rejects or misinterprets

17

Epoch in Future

Simulate future date (e.g., 2030)

Valid TIME value

18

Epoch in Past

Simulate past date (e.g., 1950)

Valid TIME value

19

Epoch in 2025

Validate TIME value for 2025

Matches expected

20

Epoch in 2000

Validate TIME value for 2000

Matches expected

21

Epoch in 1970

Validate TIME value for Unix epoch

2208988800

22

Epoch in 1900

Validate TIME = 0

Correct

23

Epoch in 2036

Validate near overflow

Max 32-bit unsigned int

24

Epoch Wraparound

Simulate post-2036 wrap

Handled or documented

25

Epoch in Leap Year

Validate 2004, 2008, etc.

Correct

26

Epoch in Non-Leap Year

Validate 2001, 2003, etc.

Correct

27

Epoch in Feb 29

Validate Feb 29 in leap years

Correct

28

Epoch in Feb 28

Validate Feb 28 in all years

Correct

29

Epoch in Dec 31

Validate end of year

Correct

30

Epoch in Jan 1

Validate start of year

Correct

31

Epoch in DST Start

Validate during DST change

No DST adjustment

32

Epoch in DST End

Validate during DST end

No DST adjustment

33

Epoch in GMT

Validate time is GMT

Always GMT

34

Epoch in Local Time

Convert to local time

Matches conversion

35

Epoch in NTP Format

Compare with NTP epoch

Offset = 70 years

36

Epoch in SNTP

Validate SNTP compatibility

Matches

37

Epoch in Logging

Log TIME value

Matches expected

38

Epoch in Monitoring

Monitor TIME values over time

Increments correctly

39

Epoch in Simulation

Simulate TIME server

Matches epoch

40

Epoch in Emulation

Emulate TIME client

Converts correctly

41

Epoch in Embedded Device

Validate on IoT device

Correct

42

Epoch in Virtual Machine

Validate in VM

Correct

43

Epoch in Cloud

Validate in cloud server

Correct

44

Epoch in Container

Validate in Docker

Correct

45

Epoch in Mobile

Validate on mobile client

Correct

46

Epoch in Browser

Convert TIME in JS

Matches expected

47

Epoch in Python

Convert TIME in Python

Matches expected

48

Epoch in Java

Convert TIME in Java

Matches expected

49

Epoch in C/C++

Convert TIME in C

Matches expected

50

Epoch in API

Validate TIME in REST API

Matches epoch

Stateless Server - Testcases

Stateless Server

S.No

Test Case

Description

Expected Result

1

Stateless TCP Request

Send TCP request

Server responds without storing state

2

Stateless UDP Request

Send UDP request

Server responds without storing state

3

Multiple UDP Requests

Send multiple UDP requests

Each handled independently

4

Multiple TCP Requests

Open/close TCP connections repeatedly

No session retained

5

No Session Memory

Send request, disconnect, reconnect

Server behaves identically

6

No Authentication State

Send request with credentials

Server ignores credentials

7

No Client Tracking

Send from different IPs

Server treats all equally

8

No Cookies

Check for cookie headers

None present

9

No Session ID

Check for session identifiers

None present

10

Stateless Logging

Check logs for session data

Only request timestamp/IP

11

Stateless Load Balancing

Use load balancer

All servers respond identically

12

Stateless Failover

Switch server mid-test

No impact on response

13

Stateless UDP Retry

Retry UDP request

Same response, no memory of previous

14

Stateless TCP Retry

Retry TCP request

Same response, no memory of previous

15

Stateless Under Load

High volume of requests

No degradation due to state

16

Stateless After Crash

Restart server

No recovery needed

17

Stateless with NAT

Send from NATed clients

Server responds without tracking

18

Stateless with VPN

Send from VPN

Server responds without tracking

19

Stateless with Proxy

Send via proxy

Server responds without tracking

20

Stateless with IPv6

Send IPv6 request

Stateless behavior maintained

21

Stateless with IPv4

Send IPv4 request

Stateless behavior maintained

22

Stateless with Invalid Data

Send malformed request

Server ignores without logging state

23

Stateless with Fragmented Packets

Send fragmented UDP

Server handles or drops without state

24

Stateless with Delayed Packets

Delay packets

Server does not wait or track

25

Stateless with Out-of-Order Packets

Send out-of-order UDP

Server handles each independently

26

Stateless with Duplicate Packets

Send duplicate UDP

Server responds to each

27

Stateless with Spoofed IP

Send from spoofed IP

Server responds without validation

28

Stateless with Port Scan

Scan ports

Server does not retain scan info

29

Stateless with Firewall

Block/reopen port

Server resumes without state loss

30

Stateless with DNS Change

Change DNS mid-test

Server unaffected

31

Stateless with Time Drift

Change system time

Server reflects new time, no state

32

Stateless with Clock Sync

Sync clock via NTP

Server reflects new time

33

Stateless with Logging Disabled

Disable logs

Server still responds

34

Stateless with Logging Enabled

Enable logs

No session data logged

35

Stateless with Rate Limiting

Apply rate limit

Server may throttle but not track

36

Stateless with TLS Attempt

Try TLS

Server does not support or track

37

Stateless with DTLS Attempt

Try DTLS

Server does not support or track

38

Stateless with Connection Drop

Drop mid-request

Server unaffected

39

Stateless with Reconnection

Reconnect immediately

Server responds normally

40

Stateless with Load Test

1000+ requests

Server handles without memory issues

41

Stateless with Client Rotation

Rotate clients

Server treats all equally

42

Stateless with Time Zone Change

Change client time zone

Server sends GMT time

43

Stateless with OS Change

Change client OS

Server responds identically

44

Stateless with Protocol Switch

Switch TCP/UDP

Server responds statelessly

45

Stateless with Packet Inspection

Inspect packets

No session info present

46

Stateless with API Gateway

Use API gateway

Server remains stateless

47

Stateless with Cloudflare

Route via Cloudflare

Server remains stateless

48

Stateless with CDN

Use CDN in front

Server remains stateless

49

Stateless with Serverless Infra

Deploy as serverless

Stateless behavior maintained

50

Stateless with Container Restart

Restart container

No state retained

Firewall Friendly - Testcases

Firewall-Friendly

S.No

Test Case

Description

Expected Result

1

TCP Port 37 Open

Check if TIME server responds on TCP port 37

Response received

2

UDP Port 37 Open

Check if TIME server responds on UDP port 37

Response received

3

TCP Port 37 Blocked

Block TCP port 37 via firewall

No response

4

UDP Port 37 Blocked

Block UDP port 37 via firewall

No response

5

TCP Port Whitelisting

Whitelist TCP port 37

Server responds

6

UDP Port Whitelisting

Whitelist UDP port 37

Server responds

7

TCP NAT Traversal

Request from behind NAT

Response received

8

UDP NAT Traversal

Request from behind NAT

Response received

9

TCP Stateful Firewall

Request through stateful firewall

Response received

10

UDP Stateless Firewall

Request through stateless firewall

Response received

11

TCP Deep Packet Inspection

Inspect TIME packet

No sensitive data exposed

12

UDP Deep Packet Inspection

Inspect TIME packet

No sensitive data exposed

13

TCP Port Forwarding

Forward port 37 to internal server

Response received

14

UDP Port Forwarding

Forward port 37 to internal server

Response received

15

TCP Connection Timeout

Simulate firewall timeout

Connection closed

16

UDP Packet Timeout

Simulate firewall timeout

No response

17

TCP Keep-Alive Blocked

Block keep-alive packets

TIME still works

18

UDP Fragment Blocked

Block fragmented UDP

TIME still works or drops

19

TCP Proxy Support

Send request via TCP proxy

Response received

20

UDP Proxy Support

Send request via UDP proxy

Response received

21

TCP Transparent Proxy

Use transparent proxy

TIME works

22

UDP Transparent Proxy

Use transparent proxy

TIME works

23

TCP Port Remapping

Remap port 37 to another port

TIME responds on new port

24

UDP Port Remapping

Remap port 37 to another port

TIME responds on new port

25

TCP Application Firewall

Pass through app-layer firewall

TIME allowed

26

UDP Application Firewall

Pass through app-layer firewall

TIME allowed

27

TCP Port Scan Detection

Scan port 37

Server logs or ignores

28

UDP Port Scan Detection

Scan port 37

Server logs or ignores

29

TCP Port Range Allowed

Allow port range including 37

TIME works

30

UDP Port Range Allowed

Allow port range including 37

TIME works

31

TCP Port Range Blocked

Block port range including 37

TIME fails

32

UDP Port Range Blocked

Block port range including 37

TIME fails

33

TCP with IDS

Use Intrusion Detection System

TIME not flagged

34

UDP with IDS

Use Intrusion Detection System

TIME not flagged

35

TCP with IPS

Use Intrusion Prevention System

TIME not blocked

36

UDP with IPS

Use Intrusion Prevention System

TIME not blocked

37

TCP with VPN

Send request over VPN

TIME works

38

UDP with VPN

Send request over VPN

TIME works

39

TCP with Split Tunneling

Use split tunnel VPN

TIME works

40

UDP with Split Tunneling

Use split tunnel VPN

TIME works

41

TCP with Cloud Firewall

Use cloud-based firewall

TIME allowed

42

UDP with Cloud Firewall

Use cloud-based firewall

TIME allowed

43

TCP with Geo-Blocking

Block by region

TIME blocked as expected

44

UDP with Geo-Blocking

Block by region

TIME blocked as expected

45

TCP with DNS Filtering

Use DNS firewall

TIME unaffected

46

UDP with DNS Filtering

Use DNS firewall

TIME unaffected

47

TCP with Port Knocking

Use port knocking to open 37

TIME works after knock

48

UDP with Port Knocking

Use port knocking to open 37

TIME works after knock

49

TCP with Zero Trust Firewall

Use zero-trust policy

TIME allowed if configured

50

UDP with Zero Trust Firewall

Use zero-trust policy

TIME allowed if configured

Cross Platform Compatibility - Testcases

Cross-Platform Compatibility

S.No

Test Case

Description

Expected Result

1

Windows 10 Client

Run TIME client on Windows 10

Time received correctly

2

Windows 11 Client

Run TIME client on Windows 11

Time received correctly

3

macOS Ventura Client

Run TIME client on macOS Ventura

Time received correctly

4

macOS Monterey Client

Run TIME client on macOS Monterey

Time received correctly

5

Ubuntu 22.04 Client

Run TIME client on Ubuntu 22.04

Time received correctly

6

Debian 12 Client

Run TIME client on Debian 12

Time received correctly

7

Fedora 39 Client

Run TIME client on Fedora 39

Time received correctly

8

Arch Linux Client

Run TIME client on Arch Linux

Time received correctly

9

Android 13 Client

Run TIME client on Android 13

Time received correctly

10

iOS 17 Client

Run TIME client on iOS 17

Time received correctly

11

Raspberry Pi OS

Run TIME client on Raspberry Pi

Time received correctly

12

FreeBSD Client

Run TIME client on FreeBSD

Time received correctly

13

Solaris Client

Run TIME client on Solaris

Time received correctly

14

Windows Server 2022

Run TIME server on Windows Server

Responds correctly

15

Linux Server

Run TIME server on Linux

Responds correctly

16

macOS Server

Run TIME server on macOS

Responds correctly

17

Docker Container

Run TIME server in Docker

Responds correctly

18

Kubernetes Pod

Run TIME server in Kubernetes

Responds correctly

19

Virtual Machine

Run TIME server in VM

Responds correctly

20

Bare Metal Server

Run TIME server on physical hardware

Responds correctly

21

x86 Architecture

Run TIME client on x86

Time received correctly

22

ARM Architecture

Run TIME client on ARM

Time received correctly

23

M1/M2 Mac

Run TIME client on Apple Silicon

Time received correctly

24

IPv4 Network

Connect over IPv4

Time received correctly

25

IPv6 Network

Connect over IPv6

Time received correctly

26

Dual Stack Network

Connect over dual stack

Time received correctly

27

Wi-Fi Network

Connect via Wi-Fi

Time received correctly

28

Ethernet Network

Connect via Ethernet

Time received correctly

29

Mobile Network

Connect via 4G/5G

Time received correctly

30

Satellite Network

Connect via satellite

Time received correctly

31

VPN Connection

Connect through VPN

Time received correctly

32

Proxy Connection

Connect through proxy

Time received correctly

33

Cloud VM (AWS)

Run TIME server on AWS EC2

Responds correctly

34

Cloud VM (Azure)

Run TIME server on Azure VM

Responds correctly

35

Cloud VM (GCP)

Run TIME server on GCP

Responds correctly

36

IoT Device

Run TIME client on IoT device

Time received correctly

37

Smart TV

Run TIME client on smart TV

Time received correctly

38

Game Console

Run TIME client on console

Time received correctly

39

Web Browser (JS Client)

Use JS to fetch TIME

Time parsed correctly

40

Python Client

Use Python script to fetch TIME

Time parsed correctly

41

Java Client

Use Java app to fetch TIME

Time parsed correctly

42

C/C++ Client

Use C/C++ app to fetch TIME

Time parsed correctly

43

Go Client

Use Go app to fetch TIME

Time parsed correctly

44

Rust Client

Use Rust app to fetch TIME

Time parsed correctly

45

Node.js Client

Use Node.js app to fetch TIME

Time parsed correctly

46

.NET Client

Use .NET app to fetch TIME

Time parsed correctly

47

Cross-Platform CLI Tool

Use CLI tool on all OS

Time received correctly

48

Cross-Platform GUI Tool

Use GUI tool on all OS

Time received correctly

49

Multi-User Environment

Multiple users on same system

All receive correct time

50

Multi-Platform Sync

Sync time across platforms

All show consistent time

No Authentication Required - Testcases

No Authentication Required

S.No

Test Case

Description

Expected Result

1

TCP Request Without Credentials

Send TCP request without credentials

Time received

2

UDP Request Without Credentials

Send UDP request without credentials

Time received

3

TCP Request With Credentials

Send TCP request with credentials

Credentials ignored, time received

4

UDP Request With Credentials

Send UDP request with credentials

Credentials ignored, time received

5

No Login Prompt

Connect to TIME server

No login prompt shown

6

No Token Required

Send request without token

Time received

7

Invalid Token Sent

Send request with invalid token

Time still received

8

Basic Auth Header Sent

Send HTTP-style auth header

Ignored, time received

9

OAuth Header Sent

Send OAuth token

Ignored, time received

10

API Key Sent

Send API key in request

Ignored, time received

11

Encrypted Credentials Sent

Send encrypted credentials

Ignored, time received

12

Auth Failure Simulation

Simulate auth failure

No effect, time received

13

Auth Required Server

Connect to server requiring auth

TIME protocol fails (not supported)

14

Auth Header Injection

Inject auth header in packet

Ignored, time received

15

Auth Query Parameter

Add auth param in URL

Ignored, time received

16

Auth in Payload

Embed auth in payload

Ignored, time received

17

Auth in TCP Options

Send auth in TCP options

Ignored, time received

18

Auth in UDP Options

Send auth in UDP options

Ignored, time received

19

Auth in DNS

Use DNS-based auth

Ignored, time received

20

Auth in Proxy

Use proxy with auth

Proxy handles auth, TIME works

21

Auth in VPN

Use VPN with auth

VPN handles auth, TIME works

22

Auth in Firewall

Firewall requires auth

TIME blocked by firewall

23

Auth in NAT

NAT requires auth

TIME blocked or NAT handles

24

Auth in Load Balancer

Load balancer requires auth

TIME works if LB handles it

25

Auth in TLS

Use TLS with auth

TIME protocol does not support TLS

26

Auth in DTLS

Use DTLS with auth

TIME protocol does not support DTLS

27

Auth in Application Layer

Application layer requires auth

TIME protocol bypasses it

28

Auth in Middleware

Middleware requires auth

TIME protocol bypasses it

29

Auth in API Gateway

API gateway requires auth

TIME protocol bypasses or fails

30

Auth in Cloud Firewall

Cloud firewall requires auth

TIME blocked or allowed

31

Auth in CDN

CDN requires auth

TIME blocked or allowed

32

Auth in WebSocket

Use WebSocket with auth

Not applicable to TIME

33

Auth in REST API

Use REST API with auth

Not applicable to TIME

34

Auth in SNMP

Use SNMP with auth

Not applicable to TIME

35

Auth in NTP

Compare with NTP auth

TIME does not support auth

36

Auth in SSH

Use SSH with auth

Not applicable to TIME

37

Auth in FTP

Use FTP with auth

Not applicable to TIME

38

Auth in HTTP

Use HTTP with auth

Not applicable to TIME

39

Auth in HTTPS

Use HTTPS with auth

Not applicable to TIME

40

Auth in MQTT

Use MQTT with auth

Not applicable to TIME

41

Auth in CoAP

Use CoAP with auth

Not applicable to TIME

42

Auth in gRPC

Use gRPC with auth

Not applicable to TIME

43

Auth in SOAP

Use SOAP with auth

Not applicable to TIME

44

Auth in Web App

Web app requires auth

TIME protocol unaffected

45

Auth in Mobile App

Mobile app requires auth

TIME protocol unaffected

46

Auth in CLI Tool

CLI tool requires auth

TIME protocol unaffected

47

Auth in GUI Tool

GUI tool requires auth

TIME protocol unaffected

48

Auth in OS

OS requires login

TIME protocol works post-login

49

Auth in BIOS

BIOS password set

TIME protocol unaffected

50

Auth in TPM

TPM-based auth enabled

TIME protocol unaffected

Legacy System Support - Testcases

Legacy System Support

S.No

Test Case

Description

Expected Result

1

Windows XP Client

Run TIME client on Windows XP

Time received correctly

2

Windows 7 Client

Run TIME client on Windows 7

Time received correctly

3

Windows 2000 Client

Run TIME client on Windows 2000

Time received correctly

4

Windows NT Client

Run TIME client on Windows NT

Time received correctly

5

MS-DOS Client

Run TIME client on MS-DOS

Time received correctly

6

macOS 10.6 (Snow Leopard)

Run TIME client on macOS 10.6

Time received correctly

7

macOS 10.4 (Tiger)

Run TIME client on macOS 10.4

Time received correctly

8

Ubuntu 10.04

Run TIME client on Ubuntu 10.04

Time received correctly

9

Debian 6

Run TIME client on Debian 6

Time received correctly

10

Red Hat 5

Run TIME client on RHEL 5

Time received correctly

11

Solaris 10

Run TIME client on Solaris 10

Time received correctly

12

AIX 7.1

Run TIME client on IBM AIX

Time received correctly

13

HP-UX 11i

Run TIME client on HP-UX

Time received correctly

14

FreeBSD 9

Run TIME client on FreeBSD 9

Time received correctly

15

NetBSD 6

Run TIME client on NetBSD 6

Time received correctly

16

OpenBSD 5

Run TIME client on OpenBSD 5

Time received correctly

17

OS/2 Warp

Run TIME client on OS/2

Time received correctly

18

BeOS

Run TIME client on BeOS

Time received correctly

19

AmigaOS

Run TIME client on AmigaOS

Time received correctly

20

VMS

Run TIME client on OpenVMS

Time received correctly

21

Legacy TCP Stack

Use old TCP/IP stack

TIME protocol works

22

Legacy UDP Stack

Use old UDP/IP stack

TIME protocol works

23

32-bit Architecture

Run on 32-bit system

Time received correctly

24

16-bit Architecture

Run on 16-bit system

Time received correctly

25

Legacy BIOS Clock Sync

Sync BIOS clock via TIME

Time updated

26

Legacy Hardware Clock

Use TIME to sync hardware clock

Time updated

27

Legacy Network Card

Use old NIC

TIME protocol works

28

Legacy Serial Modem

Use dial-up connection

TIME protocol works

29

Legacy Ethernet

Use 10 Mbps Ethernet

TIME protocol works

30

Legacy Wi-Fi (802.11b)

Use old Wi-Fi standard

TIME protocol works

31

Legacy Firewall

Pass through old firewall

TIME protocol allowed

32

Legacy NAT Device

Use old NAT router

TIME protocol works

33

Legacy Proxy Server

Use old proxy

TIME protocol works

34

Legacy DNS Resolver

Use old DNS resolver

TIME server resolved

35

Legacy Logging System

Log TIME requests

Logs correctly

36

Legacy Scheduler

Use TIME in cron or AT

Time used correctly

37

Legacy Embedded Device

Run TIME client on embedded system

Time received correctly

38

Legacy POS Terminal

Use TIME to sync POS clock

Time updated

39

Legacy SCADA System

Use TIME for SCADA sync

Time updated

40

Legacy Industrial Controller

Use TIME for PLC sync

Time updated

41

Legacy Mainframe

Use TIME on mainframe

Time received correctly

42

Legacy Terminal Emulator

Use TIME in terminal

Time displayed

43

Legacy Batch Script

Use TIME in batch file

Time parsed correctly

44

Legacy Shell Script

Use TIME in shell script

Time parsed correctly

45

Legacy C Application

Use TIME in C program

Time parsed correctly

46

Legacy Java Application

Use TIME in Java 1.4

Time parsed correctly

47

Legacy Python Script

Use TIME in Python 2.4

Time parsed correctly

48

Legacy Perl Script

Use TIME in Perl 5.8

Time parsed correctly

49

Legacy SNMP Integration

Use TIME with SNMP

Time integrated

50

Legacy System Clock Drift

Use TIME to correct drift

Time corrected

Quick Time Retrieval - Testcases

Quick Time Retrieval

S.No

Test Case

Description

Expected Result

1

TCP Time Retrieval

Request time over TCP

Response within 100ms

2

UDP Time Retrieval

Request time over UDP

Response within 50ms

3

Local Network TCP

Request time on LAN via TCP

Response < 10ms

4

Local Network UDP

Request time on LAN via UDP

Response < 5ms

5

WAN TCP

Request time over WAN via TCP

Response < 200ms

6

WAN UDP

Request time over WAN via UDP

Response < 150ms

7

High Latency Network

Simulate 300ms latency

TIME still retrieved

8

Packet Loss Simulation

Simulate 10% packet loss

TIME retrieved with retry

9

Server Under Load

Request during high server load

TIME retrieved within threshold

10

Client Under Load

Request from busy client

TIME retrieved correctly

11

Mobile Network

Request via 4G/5G

TIME retrieved < 200ms

12

Satellite Network

Request via satellite

TIME retrieved < 600ms

13

VPN Connection

Request through VPN

TIME retrieved correctly

14

Proxy Connection

Request through proxy

TIME retrieved correctly

15

Cloud Server

Request from cloud VM

TIME retrieved < 100ms

16

Docker Container

Request from container

TIME retrieved correctly

17

Virtual Machine

Request from VM

TIME retrieved correctly

18

Bare Metal Server

Request from physical server

TIME retrieved correctly

19

IPv4 Request

Request via IPv4

TIME retrieved correctly

20

IPv6 Request

Request via IPv6

TIME retrieved correctly

21

Dual Stack Request

Request via dual stack

TIME retrieved correctly

22

Multiple Requests

Send 100 requests in succession

All responses < 100ms

23

Concurrent Clients

50 clients request simultaneously

All receive time quickly

24

Time Retrieval in Python

Use Python client

TIME retrieved correctly

25

Time Retrieval in Java

Use Java client

TIME retrieved correctly

26

Time Retrieval in C

Use C client

TIME retrieved correctly

27

Time Retrieval in Go

Use Go client

TIME retrieved correctly

28

Time Retrieval in Rust

Use Rust client

TIME retrieved correctly

29

Time Retrieval in Node.js

Use Node.js client

TIME retrieved correctly

30

Time Retrieval in .NET

Use .NET client

TIME retrieved correctly

31

Time Retrieval in CLI Tool

Use command-line tool

TIME retrieved instantly

32

Time Retrieval in GUI Tool

Use GUI app

TIME displayed quickly

33

Time Retrieval in Web App

Use browser-based client

TIME retrieved correctly

34

Time Retrieval in Mobile App

Use mobile app

TIME retrieved correctly

35

Time Retrieval in Embedded Device

Use IoT device

TIME retrieved correctly

36

Time Retrieval in POS Terminal

Use POS system

TIME retrieved correctly

37

Time Retrieval in SCADA System

Use SCADA client

TIME retrieved correctly

38

Time Retrieval in PLC

Use industrial controller

TIME retrieved correctly

39

Time Retrieval in Legacy System

Use old OS

TIME retrieved correctly

40

Time Retrieval in Modern OS

Use latest OS

TIME retrieved correctly

41

Time Retrieval with DNS Resolution

Resolve server name

TIME retrieved correctly

42

Time Retrieval with IP Address

Use direct IP

TIME retrieved correctly

43

Time Retrieval with Firewall

Request through firewall

TIME retrieved correctly

44

Time Retrieval with NAT

Request from NATed client

TIME retrieved correctly

45

Time Retrieval with Load Balancer

Request via LB

TIME retrieved correctly

46

Time Retrieval with CDN

Request via CDN

TIME retrieved correctly

47

Time Retrieval with TLS Attempt

Attempt TLS

TIME not supported, fails fast

48

Time Retrieval with DTLS Attempt

Attempt DTLS

TIME not supported, fails fast

49

Time Retrieval with Invalid Packet

Send malformed request

Server ignores quickly

50

Time Retrieval with Retry Logic

Retry on failure

TIME retrieved on retry

  • Reference links