How can I alias a domain in .ssh/config?

Question

I can alias individual hosts in .ssh/config like this:

Host nickname
    Hostname host1.example.com

But sometimes I want to alias a whole domain, so as to save typing on the command line for machines on that domain:

Host *.nick
    Hostname %h.really.long.domain.example.com

That doesn't work as written, of course. Is there something that would?

Comments have suggested this question as a duplicate, but that solution doesn't work for this use case; it requires all hosts to be explicitly listed in the config file. I'm looking for a global method; I want to tell SSH 'rewrite any host of the form host???.short as host???.really.long.example.com.'

Think of it like an equivalent of sed s/.short/.really.long.etc/

https://unix.stackexchange.com/questions/61655/multiple-similar-entries-in-ssh-config — catemperor, Apr 05 '18 at 17:28
The solution there does not work for this use case. (it requires listing all hosts on the domain in question). — Andrew, Apr 05 '18 at 18:25

score 5 · Accepted Answer · answered Apr 05 '18 at 19:23

5

There's no way to perform a replacement in that manner, but it is possible to use CanonicalDomains to append domains to a hostname before attempting to check if they exist.

CanonicalDomains really.long.domain.example.com
CanonicalizeHostname yes

Host *.really.long.domain.example.com
    AdditionalDirectives

answered Apr 05 '18 at 19:23

Ignacio Vazquez-Abrams

45,725

Hrm. Wouldn't the block above have the same practical effect as Host *? – Andrew Apr 05 '18 at 20:59
2

A bit disappointing that it can't be done as desired, but oh well, a negative answer is still an answer. – Andrew Apr 05 '18 at 21:00
@Andrew: No, because Host * affects all arbitrary hosts whereas this only affects hosts that can be resolved to that FQDN. – Ignacio Vazquez-Abrams Apr 05 '18 at 22:01

How can I alias a domain in .ssh/config?

1 Answers1