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Cisco IOS Debug Command Reference, Release 12.3
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Cisco IOS Debug Command Reference Introduction
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Using Debug Commands
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Conditionally Triggered Debugging
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Debug Commands: debug aaa accounting through debug appn nof
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Debug Commands: debug appn pc through debug bundle events
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Debug Commands: debug cable env through debug ccfrfll session
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Debug Commands: debug cch323 through debug channel packets
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Debug Commands: debug clns esis events through debug crypto pki messages
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Debug Commands: debug crypto pki transactions through debug dlsw
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Debug Commands: debug dmsp doc-to-fax through debug events
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Debug Commands: debug fax relay t30 through debug gprs gtp
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Debug Commands: debug h225 through debug ip drp
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Debug Commands: debug ip dvmrp through debug ip mrouting
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Debug Commands: debug ip msdp through debug ip scp
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Debug Commands: debug ip sctp api through debug ip wccp packets
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Debug Commands: debug ipv6 cef drop through debug 12relay packets
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Debug Commands: debug lane client through debug mmoip transfer
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Debug Commands: debug modem through debug mpls ldp targeted-neighbors
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Debug Commands: debug mpls ldp transport connections through debug mpls xtagatm vc
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Debug Commands: debug mpoa client through debug oam
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Debug Commands: debug packet through debug redundancy
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Debug Commands: debug redundancy as5850 through debug rudpv1
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Debug Commands: debug saa apm through debug source error
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Debug Commands: debug source event through debug tacacs events
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Debug Commands: debug tag-switching atm-cos through debug tag-switching xtagatm vc
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Debug Commands: debug tarp events through debug video vicm
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Debug Commands: debug vlan packet through debug voip settlement enter
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Debug Commands: debug voip settlement error through debug vpm all
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Debug Commands: debug vpm dsp through debug vxml
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Debug Commands: debug x25 through voice call debug
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X.25 Cause and Diagnostic Codes
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ISDN Switch Types, Codes, and Values
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Table Of Contents
debug ip dvmrp
To display information on Distance Vector Multiprotocol Routing Protocol (DVMRP) packets received and sent, use the debug ip dvmrp command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip dvmrp [detail [access-list] [in | out]]
no debug ip dvmrp [detail [access-list] [in | out]]
Syntax Description
Command Modes
Privileged EXEC
Usage Guidelines
Use the debug ip dvmrp detail command with care. This command generates a substantial amount of output and can interrupt other activity on the router when it is invoked.
Examples
The following is sample output from the debug ip dvmrp command:
Router# debug ip dvmrpDVMRP: Received Report on Ethernet0 from 172.19.244.10DVMRP: Received Report on Ethernet0 from 172.19.244.11DVMRP: Building Report for Ethernet0 224.0.0.4DVMRP: Send Report on Ethernet0 to 224.0.0.4DVMRP: Sending IGMP Reports for known groups on Ethernet0DVMRP: Received Report on Ethernet0 from 172.19.244.10DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Building Report for Tunnel0 224.0.0.4DVMRP: Send Report on Tunnel0 to 192.168.199.254DVMRP: Send Report on Tunnel0 to 192.168.199.254DVMRP: Send Report on Tunnel0 to 192.168.199.254DVMRP: Send Report on Tunnel0 to 192.168.199.254DVMRP: Radix tree walk suspensionDVMRP: Send Report on Tunnel0 to 192.168.199.254The following lines show that the router received DVMRP routing information and placed it in the mroute table:
DVMRP: Received Report on Ethernet0 from 172.19.244.10DVMRP: Received Report on Ethernet0 from 172.19.244.11The following lines show that the router is creating a report to send to another DVMRP router:
DVMRP: Building Report for Ethernet0 224.0.0.4DVMRP: Send Report on Ethernet0 to 224.0.0.4Table 86 provides a list of internet multicast addresses supported for host IP implementations.
The following lines show that a protocol update report has been sent to all known multicast groups. Hosts use Internet Group Management Protocol (IGMP) reports to communicate with routers and to request to join a multicast group. In this case, the router is sending an IGMP report for every known group to the host, which is running mrouted. The host then responds as though the router were a host on the LAN segment that wants to receive multicast packets for the group.
DVMRP: Sending IGMP Reports for known groups on Ethernet0The following is sample output from the debug ip dvmrp detail command:
Router# debug ip dvmrp detailDVMRP: Sending IGMP Reports for known groups on Ethernet0DVMRP: Advertise group 224.2.224.2 on Ethernet0DVMRP: Advertise group 224.2.193.34 on Ethernet0DVMRP: Advertise group 224.2.231.6 on Ethernet0DVMRP: Received Report on Tunnel0 from 192.168.199.254DVMRP: Origin 150.166.53.0/24, metric 13, distance 0DVMRP: Origin 150.166.54.0/24, metric 13, distance 0DVMRP: Origin 150.166.55.0/24, metric 13, distance 0DVMRP: Origin 150.166.56.0/24, metric 13, distance 0DVMRP: Origin 150.166.92.0/24, metric 12, distance 0DVMRP: Origin 150.166.100.0/24, metric 12, distance 0DVMRP: Origin 150.166.101.0/24, metric 12, distance 0DVMRP: Origin 150.166.142.0/24, metric 8, distance 0DVMRP: Origin 150.166.200.0/24, metric 12, distance 0DVMRP: Origin 150.166.237.0/24, metric 12, distance 0DVMRP: Origin 150.203.5.0/24, metric 8, distance 0The following lines show that this group is available to the DVMRP router. The mrouted process on the host will forward the source and multicast information for this group through the DVMRP cloud to other members.
DVMRP: Advertise group 224.2.224.2 on Ethernet0The following lines show the DVMRP route information:
DVMRP: Origin 150.166.53.0/24, metric 13, distance 0DVMRP: Origin 150.166.54.0/24, metric 13, distance 0The metric is the number of hops the route has covered, and the distance is the administrative distance.
debug ip eigrp
To display information on Enhanced Interior Gateway Routing Protocol (EIGRP) protocol packets, use the debug ip eigrp command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip eigrp
no debug ip eigrp
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
This command helps you analyze the packets that are sent and received on an interface. Because the debug ip eigrp command generates a substantial amount of output, only use it when traffic on the network is light.
Examples
The following is sample output from the debug ip eigrp command:
Router# debug ip eigrpIP-EIGRP: Processing incoming UPDATE packetIP-EIGRP: Ext 192.168.3.0 255.255.255.0 M 386560 - 256000 130560 SM 360960 - 256000 104960IP-EIGRP: Ext 192.168.0.0 255.255.255.0 M 386560 - 256000 130560 SM 360960 - 256000 104960IP-EIGRP: Ext 192.168.3.0 255.255.255.0 M 386560 - 256000 130560 SM 360960 - 256000 104960IP-EIGRP: 172.69.43.0 255.255.255.0, - do advertise out Ethernet0/1IP-EIGRP: Ext 172.69.43.0 255.255.255.0 metric 371200 - 256000 115200IP-EIGRP: 192.135.246.0 255.255.255.0, - do advertise out Ethernet0/1IP-EIGRP: Ext 192.135.246.0 255.255.255.0 metric 46310656 - 45714176 596480IP-EIGRP: 172.69.40.0 255.255.255.0, - do advertise out Ethernet0/1IP-EIGRP: Ext 172.69.40.0 255.255.255.0 metric 2272256 - 1657856 614400IP-EIGRP: 192.135.245.0 255.255.255.0, - do advertise out Ethernet0/1IP-EIGRP: Ext 192.135.245.0 255.255.255.0 metric 40622080 - 40000000 622080IP-EIGRP: 192.135.244.0 255.255.255.0, - do advertise out Ethernet0/1Table 87 describes the significant fields shown in the display.
debug ip eigrp notifications
To display Enhanced Interior Gateway Routing Protocol (EIGRP) events and notifications in the console of the router, use the debug ip eigrp notifications command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip eigrp notifications
no debug ip eigrp notifications
Syntax Description
This command has no arguments or keywords.
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The output from the debug ip eigrp notifications command displays EIGRP events and notifications.
Examples
The following example output shows that the NSF-aware router has received the restart notification. The NSF-aware router will now wait for end of transmission (EOT) to be sent from the restarting neighbor (NSF-capable).
Router# debug ip eigrp notifications*Oct 4 11:39:18.092:EIGRP:NSF:AS2. Rec RS update from 135.100.10.1,00:00:00. Wait for EOT.*Oct 4 11:39:18.092:%DUAL-5-NBRCHANGE:IP-EIGRP(0) 2:Neighbor135.100.10.1 (POS3/0) is up:peer NSF restartedRelated Commands
timers nsf-route-hold
Sets the route-hold timer for NSF-aware routers that run EIGRP.
debug ip error
To display IP errors, use the debug ip error command in privileged EXEC mode. To disable debugging errors, use the no form of this command.
debug ip error access-list-number [detail] [dump]
no debug ip error
Syntax Description
Defaults
No default behavior or values
Command Modes
Privileged EXEC
Usage Guidelines
This command is used for IP error debugging. The output displays IP errors which are locally detected by this router.
CautionEnabling this command will generate output only if IP errors occur. However, if the router starts to receive many packets that contain errors, substantial output may be generated and severely affect system performance. This command should be used with caution in production networks. It should only be enabled when traffic on the IP network is low, so other activity on the system is not adversely affected. Enabling the detail and dump keywords use the highest level of system resources of the available configuration options for this command, so a high level of caution should be applied when enabling either of these keywords.
Caution
Examples
The following is sample output from the debug ip error command:
debug ip errorIP packet errors debugging is on04:04:45:IP:s=10.8.8.1 (Ethernet0/1), d=10.1.1.1, len 28, dispose ip.hopcountThe IP error in the above output was caused when the router attempted to forward a packet with a time-to-live (TTL) value of 0. The "ip.hopcount" traffic counter is incremented when a packet is dropped because of an error. This error is also displayed in the output of the show ip traffic command by the "bad hop count" traffic counter.
Table 88 describes the significant fields shown in the display.
The following is sample output from the debug ip error command enabled with the detail keyword:
debug ip error detailIP packet errors debugging is on (detailed)
1d08h:IP:s=10.0.19.100 (Ethernet0/1), d=10.1.1.1, len 28, dispose udp.noport
1d08h: UDP src=41921, dst=33434
1d08h:IP:s=10.0.19.100 (Ethernet0/1), d=10.2.2.2, len 28, dispose ip.hopcount
1d08h: UDP src=33691, dst=33434The detailed output includes layer 4 information in addition to the standard output. The IP error in the above output was caused when the router received a UDP packet when no application was listening to the UDP port. The "udp.noport" traffic counter is incremented when the router drops a UDP packet because of this error. This error is also displayed in the output of the show ip traffic command by the "no port" traffic counter under "UDP statistics."
Table 89 describes the significant fields shown in the display.
The following is sample output from the debug ip error command enabled with the detail and dump keywords:
debug ip error detail dumpIP packet errors debugging is on (detailed) (dump)1d08h:IP:s=10.0.19.100 (Ethernet0/1), d=10.1.1.1, len 28, dispose udp.noport1d08h: UDP src=37936, dst=3343403D72360: 0001 42AD4242 ..B-BB03D72370:0002FCA5 DC390800 4500001C 30130000 ..|%\9..E...0...03D72380:01116159 0A001364 0A010101 9430829A ..aY...d.....0..03D72390:0008C0AD ..@-1d08h:IP:s=10.0.19.100 (Ethernet0/1), d=10.2.2.2, len 28, dispose ip.hopcount1d08h: UDP src=41352, dst=3343403C01600: 0001 42AD4242 ..B-BB03C01610:0002FCA5 DC390800 4500001C 302A0000 ..|%\9..E...0*..03C01620:01116040 0A001364 0A020202 A188829A ..`@...d....!...03C01630:0008B253 ..2S
Note
The output from the debug ip error command, when the dump keyword is enabled, provides raw packet data in hexadecimal and ASCII forms. This addtional output is displayed in addition to the standard output. The dump keyword can be used with all of the available configuration options of this command.
Table 90 describes the standard output fields shown in the display.
Related Commands
debug ip flow export
To enable debugging output for NetFlow data export, use the debug ip flow export command in user EXEC or privileged EXEC mode. To disable debugging output for NetFlow data export, use the no form of this command.
debug ip flow export
no debug ip flow export
Syntax Description
This command has no keywords or arguments.
Defaults
Debugging output for NetFlow data export is disabled.
Command Modes
User EXEC
Privileged EXEC
Command History
12.0(1)
This command was introduced.
12.3(1)
Debugging output for NetFlow v9 data export was added.
Examples
The following is sample output from the debug ip flow export command:
Router# debug ip flow exportIP Flow export mechanism debugging is on*Mar 6 22:56:21.627:IPFLOW:Sending export pak to 1.1.1.1 port 9999*Mar 6 22:56:21.627:IPFLOW:Error sending export packet:Adjacency failureRelated Commands
debug ip ftp
To activate the debugging option to track the transactions submitted during an FTP session, use the debug ip ftp command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip ftp
no debug ip ftp
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
The debug ip ftp command is useful for debugging problems associated with FTP.
Examples
The following is an example of the debug ip ftp command:
Router# debug ip ftpFTP transactions debugging is onThe following is sample output from the debug ip ftp command:
FTP: 220 ProFTPD 1.2.0pre8 Server (DFW Nostrum FTP Server) [defiant.dfw.nostrum.com]Dec 27 22:12:09.133: FTP: ---> USER routerDec 27 22:12:09.133: FTP: 331 Password required for router.Dec 27 22:12:09.137: FTP: ---> PASS WQHK5JY2Dec 27 22:12:09.153: FTP: 230 Anonymous access granted, restrictions apply.Dec 27 22:12:09.153: FTP: ---> TYPE IDec 27 22:12:09.157: FTP: 200 Type set to I.Dec 27 22:12:09.157: FTP: ---> PASV..............Dec 27 22:12:09.173: FTP: ---> QUITDec 27 22:12:09.181: FTP: 221 Goodbye.
debug ip http all
To enable debugging output for all HTTP processes on the system, use the debug ip http all command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http all
no debug ip http all
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Privileged EXEC
Command History
Usage Guidelines
This command enables debugging messages for all HTTP processes and activity. Issuing this command is equivalent to issuing the following commands:
•
•
•
•
•
•
Examples
For sample output and field descriptions of this command, see the documentation of the commands listed in the "Usage Guidelines" section.
Related Commands
debug ip http authentication
To troubleshoot HTTP authentication problems, use the debug ip http authentication command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http authentication
no debug ip http authentication
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
The debug ip http authentication command displays the authentication method the router attempted and authentication-specific status messages.
Examples
The following is sample output from the debug ip http authentication command:
Router# debug ip http authenticationAuthentication for url `/' `/' level 15 privless `/'Authentication username = `local15' priv-level = 15 auth-type = localTable 91 describes the significant fields shown in the display.
debug ip http ezsetup
To display the configuration changes that occur during the EZ Setup process, use the debug ip http ezsetup command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http ezsetup
no debug ip http ezsetup
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
Use the debug ip http ezsetup command to verify the EZ Setup actions without changing the configuration of the router.
EZ Setup is a form you fill out to perform basic router configuration from most HTML browsers.
Examples
The following is sample output from the debug ip http ezsetup that shows the configuration changes for the router when the EZ Setup form has been submitted:
Router# debug ip http ezsetupservice timestamps debugservice timestamps logservice password-encryption!hostname router-name!enable secret router-pwline vty 0 4password router-pw!interface ethernet 0ip address 172.69.52.9 255.255.255.0no shutdownip helper-address 172.31.2.132ip name-server 172.31.2.132isdn switch-type basic-5essusername Remote-name password Remote-chapinterface bri 0ip unnumbered ethernet 0encapsulation pppno shutdowndialer map ip 192.168.254.254 speed 56 name Remote-name Remote-numberisdn spid1 spid1isdn spid2 spid2ppp authentication chap callindialer-group 1!ip classlessaccess-list 101 deny udp any any eq snmpaccess-list 101 deny udp any any eq ntpaccess-list 101 permit ip any anydialer-list 1 list 101ip route 0.0.0.0 0.0.0.0 192.168.254.254ip route 192.168.254.254 255.255.255.255 bri 0logging bufferedsnmp-server community public ROip http serverip classlessip subnet-zero!endRelated Commands
Displays individual tokens parsed by the HTTP server.
Displays HTTP server transaction processing.
Displays the URLs accessed from the router.
debug ip http ssi
To display information about the HTML SSI EXEC command or HTML SSI ECHO command, use the debug ip http ssi command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http ssi
no debug ip http ssi
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Examples
The following is sample output from the debug ip http ssi command:
Router# debug ip http ssiHTML: filtered command `exec cmd="show users"'HTML: SSI command `exec'HTML: SSI tag `cmd' = "show users"HTML: Executing CLI `show users' in mode `exec' doneThe following line shows the contents of the SSI EXEC command:
HTML: filtered command `exec cmd="show users"'The following line indicates the type of SSI command that was requested:
HTML: SSI command `exec'The following line shows the argument show users assigned to the tag cmd:
HTML: SSI tag 'cmd' = "show users"The following line indicates that the show users command is being executed in EXEC mode:
HTML: Executing CLI `show users' in mode `exec' donedebug ip http ssl error
To enable debugging messages for the HTTP secure (HTTPS) web server and client, use the debug ip http ssl error command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http ssl error
no debug ip http ssl error
Syntax Description
This command has no arguments or keywords.
Defaults
Debugging message output is disabled.
Command Modes
Privileged EXEC
Command History
Examples
None.
Related Commands
debug ip http token
To display individual tokens parsed by the HTTP server, use the debug ip http token command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http token
no debug ip http token
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
Use the debug ip http token command to display low-level HTTP server parsings. To display high-level HTTP server parsings, use the debug ip http transaction command.
Examples
The following is part of a sample output from the debug ip http token command. In this example, the browser accessed the router's home page http://router-name/. The output gives the token parsed by the HTTP server and its length.
Router# debug ip http tokenHTTP: token len 3: 'GET'HTTP: token len 1: ' 'HTTP: token len 1: '/'HTTP: token len 1: ' 'HTTP: token len 4: 'HTTP'HTTP: token len 1: '/'HTTP: token len 1: '1'HTTP: token len 1: '.'HTTP: token len 1: '0'HTTP: token len 2: '\15\12'HTTP: token len 7: 'Referer'HTTP: token len 1: ':'HTTP: token len 1: ' 'HTTP: token len 4: 'http'HTTP: token len 1: ':'HTTP: token len 1: '/'HTTP: token len 1: '/'HTTP: token len 3: 'www'HTTP: token len 1: '.'HTTP: token len 3: 'thesite'HTTP: token len 1: '.'HTTP: token len 3: 'com'HTTP: token len 1: '/'HTTP: token len 2: '\15\12'HTTP: token len 10: 'Connection'HTTP: token len 1: ':'HTTP: token len 1: ' 'HTTP: token len 4: 'Keep'HTTP: token len 1: '-'HTTP: token len 5: 'Alive'HTTP: token len 2: '\15\12'HTTP: token len 4: 'User'HTTP: token len 1: '-'HTTP: token len 5: 'Agent'HTTP: token len 1: ':'HTTP: token len 1: ' 'HTTP: token len 7: 'Mozilla'HTTP: token len 1: '/'HTTP: token len 1: '2'HTTP: token len 1: '.'...Related Commands
Displays the configuration changes that occur during the EZ Setup process.
Displays HTTP server transaction processing.
Displays the URLs accessed from the router.
debug ip http transaction
To display HTTP server transaction processing, use the debug ip http transaction command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http transaction
no debug ip http transaction
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
Use the debug ip http transaction command to display what the HTTP server is parsing at a high level. To display what the HTTP server is parsing at a low level, use the debug ip http token command.
Examples
The following is sample output from the debug ip http transaction command. In this example, the browser accessed the router's home page http://router-name/.
Router# debug ip http transactionHTTP: parsed uri '/'HTTP: client version 1.0HTTP: parsed extension RefererHTTP: parsed line http://www.company.com/HTTP: parsed extension ConnectionHTTP: parsed line Keep-AliveHTTP: parsed extension User-AgentHTTP: parsed line Mozilla/2.01 (X11; I; FreeBSD 2.1.0-RELEASE i386)HTTP: parsed extension HostHTTP: parsed line router-nameHTTP: parsed extension AcceptHTTP: parsed line image/gif, image/x-xbitmap, image/jpeg, image/HTTP: parsed extension AuthorizationHTTP: parsed authorization type BasicHTTP: received GET ''Table 92 describes the significant fields shown in the display.
Related Commands
Displays the configuration changes that occur during the EZ Setup process.
Displays individual tokens parsed by the HTTP server.
Shows the URLs accessed from the router.
debug ip http url
To show the URLs accessed from the router, use the debug ip http url command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip http url
no debug ip http url
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
Use the debug ip http url command to keep track of the URLs that are accessed and to determine from which hosts the URLs are accessed.
Examples
The following output is from the debug ip http url command. In this example, the HTTP server accessed the URLs and /exec. The output shows the URL being requested and the IP address of the host requesting the URL.
Router# debug ip http urlHTTP: processing URL '/' from host 172.31.2.141HTTP: processing URL '/exec' from host 172.31.2.141Related Commands
Displays the configuration changes that occur during the EZ Setup process.
Displays individual tokens parsed by the HTTP server.
Displays HTTP server transaction processing.
debug ip icmp
To display information on Internal Control Message Protocol (ICMP) transactions, use the debug ip icmp command in privileged EXEC mode. To disable debugging output, use the no form of this command.
debug ip icmp
no debug ip icmp
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Usage Guidelines
This command helps you determine whether the router is sending or receiving ICMP messages. Use it, for example, when you are troubleshooting an end-to-end connection problem.
Note
Examples
The following is sample output from the debug ip icmp command:
Router# debug ip icmpICMP: rcvd type 3, code 1, from 10.95.192.4ICMP: src 10.56.0.202, dst 172.69.16.1, echo replyICMP: dst (10.120.1.0) port unreachable rcv from 10.120.1.15ICMP: src 172.69.12.35, dst 172.69.20.7, echo replyICMP: dst (255.255.255.255) protocol unreachable rcv from 10.31.7.21ICMP: dst (10.120.1.0) port unreachable rcv from 10.120.1.15ICMP: dst (255.255.255.255) protocol unreachable rcv from 10.31.7.21ICMP: dst (10.120.1.0) port unreachable rcv from 10.120.1.15ICMP: src 10.56.0.202, dst 172.69.16.1, echo replyICMP: dst (10.120.1.0) port unreachable rcv from 10.120.1.15ICMP: dst (255.255.255.255) protocol unreachable rcv from 10.31.7.21ICMP: dst (10.120.1.0) port unreachable rcv from 10.120.1.15Table 93 describes the significant fields shown in the display.
Table 94 describes the significant fields shown in the second line of the display.
Other messages that the debug ip icmp command can generate follow.
When an IP router or host sends out an ICMP mask request, the following message is generated when the router sends a mask reply:
ICMP: sending mask reply (255.255.255.0) to 172.69.80.23 via Ethernet0The following two lines are examples of the two forms of this message. The first form is generated when a mask reply comes in after the router sends out a mask request. The second form occurs when the router receives a mask reply with a nonmatching sequence and ID. Refer to Appendix I of RFC 950, Internet Standard Subnetting Procedures, for details.
ICMP: mask reply 255.255.255.0 from 172.69.80.31ICMP: unexpected mask reply 255.255.255.0 from 172.69.80.32The following output indicates that the router sent a redirect packet to the host at address 172.69.80.31, instructing that host to use the gateway at address 172.69.80.23 in order to reach the host at destination address 172.69.1.111:
ICMP: redirect sent to 172.69.80.31 for dest 172.69.1.111 use gw 172.69.80.23The following message indicates that the router received a redirect packet from the host at address 172.69.80.23, instructing the router to use the gateway at address 172.69.80.28 in order to reach the host at destination address 172.69.81.34:
ICMP: redirect rcvd from 172.69.80.23 -- for 172.69.81.34 use gw 172.69.80.28The following message is displayed when the router sends an ICMP packet to the source address (172.69.94.31 in this case), indicating that the destination address (172.69.13.33 in this case) is unreachable:
ICMP: dst (172.69.13.33) host unreachable sent to 172.69.94.31The following message is displayed when the router receives an ICMP packet from an intermediate address (172.69.98.32 in this case), indicating that the destination address (172.69.13.33 in this case) is unreachable:
ICMP: dst (172.69.13.33) host unreachable rcv from 172.69.98.32Depending on the code received (as Table 93 describes), any of the unreachable messages can have any of the following "strings" instead of the "host" string in the message:
netprotocolport
