Ping ignores the timeout in some cases

[MartinKolarik]

Multiple weird things in this measurement, reproducible for the probes/target combination:

• the ping command runs for about 30 seconds even though we set a 10-second timeout
• there is always only 1 packet with around 2 ms RTT, but it takes more than 10 seconds to appear in the output
• no other lost or awaited packets reported
• 0.000 total time

PING hk-hkg-as32167.anchors.atlas.ripe.net(2a0c:9a40:9dd7:1::2) 56 data bytes
64 bytes from 2a0c:9a40:9dd7:1::2: icmp_seq=1 ttl=60 time=2.67 ms

--- hk-hkg-as32167.anchors.atlas.ripe.net ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 2.665/2.665/2.665/0.000 ms

[MartinKolarik]

@SukkaW I see you own one of the two probes in the location, maybe you could try running a ping with extra debugging output to help us better understand what's happening there :

ping -6 -O -c 3 -i 0.5 -w 10 -D -v hk-hkg-as32167.anchors.atlas.ripe.net

[SukkaW]

@SukkaW I see you own one of the two probes in the location, maybe you could try running a ping with extra debugging output to help us better understand what's happening there :

ping -6 -O -c 3 -i 0.5 -w 10 -D -v hk-hkg-as32167.anchors.atlas.ripe.net

Sure! Here is the output:

root@hk-skywolf:~# ping -6 -O -c 3 -i 0.5 -w 10 -D -v hk-hkg-as32167.anchors.atlas.ripe.net
ping: sock4.fd: -1 (socktype: 0), sock6.fd: 3 (socktype: SOCK_RAW), hints.ai_family: AF_INET6

ai->ai_family: AF_INET6, ai->ai_canonname: 'hk-hkg-as32167.anchors.atlas.ripe.net'
PING hk-hkg-as32167.anchors.atlas.ripe.net(2a0c:9a40:9dd7:1::2) 56 data bytes
[1737268228.134040] 64 bytes from 2a0c:9a40:9dd7:1::2: icmp_seq=1 ident=10238 ttl=60 time=1.40 ms

--- hk-hkg-as32167.anchors.atlas.ripe.net ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 1.399/1.399/1.399/0.000 ms

Note that the command took very long to finish:

real    0m32.414s
user    0m0.014s
sys     0m0.006s

[SukkaW]

@MartinKolarik Since I am kinda familiar with the operator of AS7720, if this weird behavior only happens with AS7720 I can ask them if they know anything.