Comment 5 for bug 1669501

juju ssh uses ReachableHostPort which attempted to check of the tcp port is reachable before trying to ssh to that port. This check is triggering sshguard.

https://github.com/juju/juju/blob/staging/cmd/juju/commands/ssh_common.go#L408

This file has changed since 2.0.3, but given mbruzek has the same behavior, it seems the behavior has changed.