On Wed, 8 May 2024 at 20:39, Patrik Ek <ek.patrik@xxxxxxxxx> wrote:
[...]
> user1@XXXX[12:18][home/user1/Desktop]$ ssh -V
> OpenSSH_9.6p1, OpenSSL 3.1.5 30 Jan 2024
That's OpenSSH. What platform is it on? The behaviour of the
resolver libraries might be a factor.
> user1@XXXX[12:18][home/user1/Desktop]$
> /app/moshell/24.0f/moshell/commonjars/ssh.lin64
> user@2001:1:8100:a3::fe
That is not the same binary you just showed the version of.
> ignoring bad CNAME "2001:1:8100:a3::fe" for host "2001:1:8100:a3::fe":
> domain name "2001:1:8100:a3::fe" contains invalid characters
> ssh: connect to host 2001:1:8100:a3::fe port 22: Connection refused
> user1@XXXX[12:18][home/user1/Desktop]$
>
> Usernames, hostnames and IP addresses are replaced with other values.
> It is apparently able to establish a connection with the destination,
> even though port 22 is not in use. Does anyone know why OpenSSH treats
> valid IPv6 addresses as CNAMEs and tries to do a DNS lookup on these?
Do you have CanonicalizePermittedCNAMEs or VerifyHostKeyDNS set in
your config? Does it do the same thing if you load an empty config?
("ssh -F /dev/null ...").
Running with full debugging (ssh -vvv) might shed some light. Here's
what it looks like on Fedora:
$ ssh -vvv -F /dev/null user@2001:1:8100:a3::fe
OpenSSH_9.6p1, OpenSSL 3.0.9 30 May 2023
debug1: Reading configuration data /dev/null
debug2: resolve_canonicalize: hostname 2001:1:8100:a3::fe is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' ->
'/home/dtucker/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' ->
'/home/dtucker/.ssh/known_hosts2'
debug3: channel_clear_timeouts: clearing
debug3: ssh_connect_direct: entering
debug1: Connecting to 2001:1:8100:a3::fe [2001:1:8100:a3::fe] port 22.
debug3: set_sock_tos: set socket 3 IPV6_TCLASS 0x48
--
Darren Tucker (dtucker at dtucker.net)
GPG key 11EAA6FA / A86E 3E07 5B19 5880 E860 37F4 9357 ECEF 11EA A6FA
Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.
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