I'm trying to create an IP header in C. typedef struct header { //IP-Header unsigned char ip_v:4, ip_hl:4;/* this means that each member is 4 bits */ unsigned char ip_tos; //1 Byte unsigned short int ip_len; //2 Byte unsigned short int ip_id; //2 Byte unsigned short int ip_off; //2 Byte unsigned char ip_ttl; //1 Byte unsigned char ip_p; //1 Byte unsigned short int ip_sum; //2 Byte unsigned int
Wireshark · Display Filter Reference: Internet Protocol Field name Description Type Versions; ip.addr: Source or Destination Address: IPv4 address: 1.0.0 to 3.2.5: ip.bogus_header_length: Bogus IP header length: Label DHCP (Dynamic Host Configuration Protocol) Basics DHCP (Dynamic Host Configuration Protocol) Basics. 5/26/2020; 14 minutes to read; In this article. Dynamic Host Configuration Protocol (DHCP) is a standard protocol defined by RFC 1541 (which is superseded by RFC 2131) that allows a server to dynamically distribute IP addressing and configuration information to clients.
Header Length (4-bit)—The length in octets of the header size up to the Payload field. Type of Service (TOS) (8-bit)—Specifies the treatment of the datagram during its transmission through the routers. This field can also be interpreted as Differentiated Services Code Point (DSCP). Total Length (16-bit)—The size of the IP packet in octets
Need for "Total Length" in IP header - Cisco Community IP header has two fields IHL and Total length. Below is the reason I found for having both these fields instead of one. "The Total Length field is required in the header because some lower-layer protocols that carry IPv4 datagrams do not (accurately) convey the size of encapsulated datagrams on their own. TCP IP Packet Format | Ethernet header,IP header,TCP header IP header: 17-18: T-len: Total length of packet in bytes including IP header: IP header: 19-20: ID: Unique Identification of packet: IP header: 21: Flags: 3 bits (0-DF-MF) DF=0 May fragment,MF=0 last fragment: IP header: 21-22: Offset: Fragment offset in 64 bit blocks: IP header: 23: TTL: Time to live: IP header: 24: Protocol: Upper layer
IPv4 header | CCNA
Manual Packet Analysis - Infosec Resources Sep 24, 2012 Fragmentation at Network Layer - GeeksforGeeks Efficiency (e) = useful/total = (Data without header)/(Data with header) Throughput = e * B { where B is bottleneck bandwidth } Example – An IP router with a Maximum Transmission Unit (MTU) of 200 bytes has received an IP packet of size 520 bytes with an IP header of length 20 bytes. The values of the relevant fields in the IP header. Chapter 5. The Internet Protocol (IP) - Shichao's Notes