TCP IP Illustrated

6 source route failed section 85 destination network

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ibited network unreachable for TOS (Section 9.3) host unreachable for TOS (Section 9.3) communication administratively prohibited by filtering host precedence violation precedence cutoff in effect 0 source quench (elementary flow control. Section 11.11) * 0 1 2 3 redirect (Section 9.5): redirect for network redirect for host redirect for type-of-service and network redirect for type-of-service and host * * * * 8 0 echo request (Ping request. Chapter 7) * 9 10 0 0 router advertisement (Section 9.6) router solicitation (Section 9.6) * * 3 4 5 11 12 0 1 0 1 Description time exceeded: time-to-live equals 0 during transit (Traceroute, Chapter 8) time-to-live equals 0 during reassembly (Section 11.5) parameter problem: IP header bad (catchall error) required option missing Query Error * * * * * * * * * * * * * * * * * * * * * file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/icmp_int.htm (3 of 16) [12/09/2001 14.46.42] Chapter 6. ICMP: Internet Control Message Protocol 13 14 0 0 timestamp request (Section 6.4) timestamp reply (Section 6.4) * * 15 16 0 0 information request (obsolete) information reply (obsolete) * * 17 18 0 0 address mask request (Section 6.3) address mask reply (Section 6.3) * * Figure 6.3 ICMP message types. These rules are meant to prevent the broadcast storms that have occurred in the past when ICMP errors were sent in response to broadcast packets. 6.3 ICMP Address Mask Request and Reply The ICMP address mask request is intended for a diskless system to obtain its subnet mask (Section 3.5) at bootstrap time. The requesting system broadcasts its ICMP request. (This is similar to a diskless system using RARP to obtain its IP address at bootstrap time.) An alternative method for a diskless system to obtain its subnet mask is the BOOTP protocol, which we describe in Chapter 16. Figure 6.4 shows the format of the ICMP address mask request and reply messages. Figure 6.4 ICMP address mask request and reply messages. The identifier and sequence number fields in the ICMP message can be set to anything the sender chooses, and these...
View Full Document

Ask a homework question - tutors are online