Issue with ping source address display
From: Daniele Orlandi <hidden>
Date: 2014-09-16 16:13:50
Hello, I noticed that when ping receives ICMP messages from different sources the first IP address is always used and displayed: vihai@seviolab:~$ ping -V ping utility, iputils-s20121221 This is a (simulated) flapping route: vihai@seviolab:~$ ping 10.254.10.140 PING 10.254.10.140 (10.254.10.140) 56(84) bytes of data. From 192.168.1.1 icmp_seq=1 Destination Host Unreachable From 192.168.1.1 icmp_seq=2 Destination Host Unreachable From 192.168.1.1 icmp_seq=3 Destination Host Unreachable 64 bytes from 192.168.1.1: icmp_seq=4 ttl=61 time=24.7 ms 64 bytes from 192.168.1.1: icmp_seq=5 ttl=61 time=25.6 ms 64 bytes from 192.168.1.1: icmp_seq=6 ttl=61 time=69.6 ms From 192.168.1.1 icmp_seq=7 Destination Host Unreachable From 192.168.1.1 icmp_seq=8 Destination Host Unreachable From 192.168.1.1 icmp_seq=9 Destination Host Unreachable ^C
--- 10.254.10.140 ping statistics ---9 packets transmitted, 3 received, +6 errors, 66% packet loss, time 8001ms
rtt min/avg/max/mdev = 24.797/40.061/69.692/20.955 ms
The sources, however are different:
vihai@seviolab:~$ sudo tcpdump -n icmp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
^[OA^[OA^[OA17:09:55.932981 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 1, length 64
17:09:55.933234 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
17:09:56.933169 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 2, length 64
17:09:56.933416 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
17:09:57.933160 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 3, length 64
17:09:57.933404 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
17:09:58.933163 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 4, length 64
17:09:58.957939 IP 10.254.10.140 > 192.168.1.21: ICMP echo reply, id 9278, seq 4, length 64
17:09:59.935050 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 5, length 64
17:09:59.960724 IP 10.254.10.140 > 192.168.1.21: ICMP echo reply, id 9278, seq 5, length 64
17:10:00.936177 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 6, length 64
17:10:01.005849 IP 10.254.10.140 > 192.168.1.21: ICMP echo reply, id 9278, seq 6, length 64
17:10:01.936313 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 7, length 64
17:10:01.936626 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
17:10:02.935321 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 8, length 64
17:10:02.935591 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
17:10:03.934322 IP 192.168.1.21 > 10.254.10.140: ICMP echo request, id 9278, seq 9, length 64
17:10:03.934613 IP 192.168.1.1 > 192.168.1.21: ICMP host 10.254.10.140 unreachable, length 92
Tried with a different ping implementation (RouterOS) and the behaviour seems correct:
[vihai@SevioLab SW1] > ping 10.254.10.140
HOST SIZE TTL TIME STATUS
192.168.1.1 84 64 0ms host unreachable
192.168.1.1 84 64 0ms host unreachable
192.168.1.1 84 64 0ms host unreachable
10.254.10.140 56 61 20ms
10.254.10.140 56 61 46ms
10.254.10.140 56 61 37ms
192.168.1.1 84 64 0ms host unreachable
192.168.1.1 84 64 0ms host unreachable
192.168.1.1 84 64 0ms host unreachable
sent=9 received=3 packet-loss=66% min-rtt=20ms avg-rtt=34ms max-rtt=46ms
I think you may be interested as this issue caught me in a troubleshooting session introducing strangeness and might do the same to you too :)
Bye,