[Bug 2096914] Re: rsync 3.3.0-1ubuntu0.1 patch breaks IPv6 over SSH: "ssh: Could not resolve hostname x: Name or service not known"

[Benjamin Schmid]

I highly assume this patch removing the need to run `reconfigure` is the actual culprit:
https://git.launchpad.net/ubuntu/+source/rsync/commit/?h=applied/ubuntu/oracular-updates&id=084fca0e7f6e8a9414c8674962a0a93b5877d34b

For other readers: My current easy-to-go workaround is to switch the the Debian version in testing / trixie, which does not exhibit this error, but contains the critical CVE patches from 15 Jan 2025:
https://packages.debian.org/trixie/rsync

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to rsync in Ubuntu.
https://bugs.launchpad.net/bugs/2096914

Title:
  rsync 3.3.0-1ubuntu0.1 patch breaks IPv6 over SSH: "ssh: Could not
  resolve hostname x: Name or service not known"

Status in rsync package in Ubuntu:
  New

Bug description:
  The security upgrade of rsync from 3.3.0-1 (oracular) to
  3.3.0-1ubuntu0.1 (oracular-updates) breaks my current rsync over SSH
  backup for an IPv6-only target host!:

      rsync -a --delete -s --rsh="ssh -vvvv" -p 22 /tmp/emptydir/
  admin at ipv6only.reachable.nas:/share/CACHEDEV3_DATA/targetdir

  
  3.3.0-1ubuntu0.1 outputs here:

  OpenSSH_9.7p1 Ubuntu-7ubuntu4.1, OpenSSL 3.3.1 4 Jun 2024
  debug1: Reading configuration data /etc/ssh/ssh_config
  [...]
  debug3: resolve_host: lookup ipv6only.reachable.nas:22
  ssh: Could not resolve hostname ipv6only.reachable.nas: Name or service not known
  rsync: connection unexpectedly closed (0 bytes received so far) [sender]
  rsync error: unexplained error (code 255) at io.c(232) [sender=3.3.0]

  
  while 3.3.0-1 outputs here:

  OpenSSH_9.7p1 Ubuntu-7ubuntu4.1, OpenSSL 3.3.1 4 Jun 2024
  debug1: Reading configuration data /etc/ssh/ssh_config
  [...]
  debug3: resolve_host: lookup ipv6only.reachable.nas:22
  debug3: channel_clear_timeouts: clearing
  debug3: ssh_connect_direct: entering
  debug1: Connecting to ipv6only.reachable.nas [2001:9e8:…] port 22.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/rsync/+bug/2096914/+subscriptions