IPv4 Example

Basic IPv4

Examine a basic IPv4 packet with complete header analysis. Learn version, IHL, TOS, total length, identification, flags, fragment offset, TTL, protocol, checksum, source and destination addresses.

Hex Data

45 00 00 3C 12 34 00 00 40 06 7C 7F C0 A8 01 02 C0 A8 01 01
Note: Version 4, IHL 5 (20-byte header), TTL 64, protocol TCP (6)
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Field Breakdown

Version
IP version (always 4 for IPv4)
69
IHL
Internet Header Length in 32-bit words (minimum 5)
69
DSCP
Differentiated Services Code Point (QoS)
0b000000
ECN
Explicit Congestion Notification
0b00
Total Length
Total length of IP packet in bytes (header + data)
60
Identification
Unique identifier for fragmentation reassembly
0x1234
Flags
Control flags (Reserved, DF, MF)
0b000
Fragment Offset
Position of fragment in original datagram (in 8-byte blocks)
0
TTL
Time To Live (hop limit)
64
Protocol
Protocol used in data portion
6
TCP
Header Checksum
Checksum of IP header only
0x7C7F
Source IP
Source IP address
0x-3F57FEFE
Destination IP
Destination IP address
0x-3F57FEFF

Related Resources

IPv4 Protocol Visualizer - Parse & Analyze IPv4 PacketsIPv4 Header Format and Fields Explained - ByteLensIPv4 vs IPv6 - Key Differences and Migration GuideIP Address Protocol - What is IP? IPv4 vs IPv6 Explained

About IPv4

Internet Protocol version 4 (RFC 791)

Fields: 13
Endianness: big
Specification: RFC 791