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. _______________________________________________ openssh-unix-dev mailing list openssh-unix-dev@xxxxxxxxxxx https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev