Comment 12 for bug 1744318

old version tries to connect to port 80, hangs because I blocked it.

[pid 1035] connect(3, {sa_family=AF_INET, sin_port=htons(80), sin_addr=inet_addr("91.189.95.15")}, 16) = -1 EINPROGRESS (Operation now in progress)
[pid 1035] poll([{fd=3, events=POLLOUT|POLLERR}], 1, 20000

afterwards it uses HTTPS:

# strace -e connect -f do-release-upgrade
[...]
[pid 8264] connect(3, {sa_family=AF_INET, sin_port=htons(443), sin_addr=inet_addr("91.189.95.15")}, 16) = 0
[pid 8264] connect(3, {sa_family=AF_INET6, sin6_port=htons(443), inet_pton(AF_INET6, "2001:67c:1560:8008::11", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = 0
[pid 8264] connect(3, {sa_family=AF_INET, sin_port=htons(443), sin_addr=inet_addr("91.189.95.15")}, 16) = -1 EINPROGRESS (Operation now in progress)
[pid 8264] +++ exited with 0 +++
strace: Process 8265 attached
[pid 8265] +++ exited with 0 +++
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=8265, si_uid=0, si_status=0, si_utime=0, si_stime=1} ---
strace: Process 8266 attached
[pid 8266] +++ exited with 0 +++
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=8266, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
Please install all available updates for your release before upgrading.
+++ exited with 1 +++

I can't get this container to actually show me there's an update availagble, but it works fine in another, maybe I broke some cache file?