[Bug 1771353] Re: Server feature level is now lower than when we began our transaction. Restarting with new ID

[Steve Dodd]

The patch "resolved-Mitigate-DVE-2018-0001-by-retrying-NXDOMAIN-
with.patch" for bug #1727237 seems to be the root cause of my problems
(now reported separately in bug #1785383.)

As the patch changes the transaction restart logic it may be worth the
OP rebuilding without that patch and retesting.

@xnox: my understanding is still that upstream recommendation is to use
libnss-resolve, it is still there in the latest man pages. The handling
of resolv.conf is to a certain extent orthogonal, as that file is only
used by systemd to exchange nameserver info with "legacy" code..

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Title:
  Server feature level is now lower than when we began our transaction.
  Restarting with new ID

Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  systemd 237-3ubuntu10 from bionic

  There is no /etc/netplan/* file.

  I'm getting some sort of a loop when systemd-resolved tries to resolve
  the hostname of my canonistack instance:

  ubuntu at bip:~$ systemd-resolve bip.lcy02.canonistack
  bip.lcy02.canonistack: resolve call failed: All attempts to contact name servers or networks failed

  systemd-resolved debug output loops over like this:
  Transaction 36341 is now 19121.
  Cache miss for bip.lcy02.canonistack IN A
  Transaction 19121 for <bip.lcy02.canonistack IN A> scope dns on */*.
  Using feature level UDP+EDNS0 for transaction 19121.
  Sending query packet with id 19121.
  Processing incoming packet on transaction 19121. (rcode=SUCCESS)
  Server feature level is now lower than when we began our transaction. Restarting with new ID.
  Transaction 19121 is now 17157.
  Cache miss for bip.lcy02.canonistack IN A
  Transaction 17157 for <bip.lcy02.canonistack IN A> scope dns on */*.
  Using feature level UDP+EDNS0 for transaction 17157.
  Sending query packet with id 17157.
  Processing incoming packet on transaction 17157. (rcode=SUCCESS)
  Server feature level is now lower than when we began our transaction. Restarting with new ID.
  ...

  Packet capture shows a loop like this:
  13:38:32.293524 IP 10.55.32.54.53786 > 10.55.32.1.53: 46096+ [1au] A? bip.lcy02.canonistack. (50)
  13:38:32.293753 IP 10.55.32.1.53 > 10.55.32.54.53786: 46096* 1/0/0 A 10.55.32.54 (55)
  13:38:32.294026 IP 10.55.32.54.53786 > 10.55.32.1.53: 64494+ [1au] A? bip.lcy02.canonistack. (50)
  13:38:32.294249 IP 10.55.32.1.53 > 10.55.32.54.53786: 64494* 1/0/0 A 10.55.32.54 (55)

  I'm going to attach the full debug output, and the pcap file.

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