Bug#912524: snapshot.debian.org is unreachable from (apparently) 126.96.36.199/9
Mozilla uses snapshot.debian.org as a way to generate deterministic
docker images for its CI. Those docker images are built from Amazon EC2
instance, and we've had recurring intermittent errors connecting to
snapshot.debian.org. After having been able to observe the problem first
hand (as in, with shell access), I've determined some interesting
- While I originally was assuming that snapshot.debian.org was just
down at the time we were getting the errors, it turns out it *is*
available from other places of the internet (like other EC2 instances
or my own machine at home).
- When that happens, *both* snapshot.debian.org IPv4 addresses are
unreachable (188.8.131.52 and 184.108.40.206).
- Traceroute stops at the last router before those hosts. That is, the
first "* * *" hop is where, on a machine where it's reachable,
snapshot.debian.org would appear.
- Looking back at the logs from all the jobs we've had in the past
failing to reach snapshot.debian.org (or at least, marked as such),
the IP addresses of the hosts they were running on (as well as the IP
address of the host I had direct access to and that couldn't connect
to snapshot.debian.org) were all in the 220.127.116.11/9 block.
1. Full list: