Cisco IOS Cookbook, 2nd Edition

Viewing Tunnel Status

Problem

You want to check the status of a tunnel.

Solution

You can look at the attributes for a tunnel with the show interface command.

Router1#show interface Tunnel5

And the easiest way to determine if a tunnel is operational is simply to use a PING test to either the send ICMP packets through the tunnel or to its destination address:

Router1#ping 192.168.66.6
Router1#ping 172.22.1.4

Discussion

You can use the standard show interface command on a tunnel interface to see a considerable amount of useful information about it:

Router1#show interface Tunnel5 Tunnel5 is up, line protocol is up Hardware is Tunnel Internet address is 192.168.66.5/30 MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation TUNNEL, loopback not set Keepalive not set Tunnel source 172.22.1.3, destination 172.22.1.4 Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled Tunnel TTL 255 Checksumming of packets disabled, fast tunneling enabled Last input 1d19h, output 00:00:06, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 79 Queueing strategy: fifo Output queue: 0/0 (size/max) 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 2536 packets input, 1386605 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 23235 packets output, ...