AW: CanonicalHostname and ssh connections through a jumphost

[Brian Candler]

On 20/05/2020 09:58, Warlich, Christof wrote:
>> That sounds like a chicken-and-egg situation. You have:
>>
>> host *.example.com
>>     ProxyJump blah
>>
>> but you don't know that you should use this entry until you know that the unqualified name can be qualified to *.example.com.
>>
>> ISTM that if you want the ProxyJump host to work that way, you'd have to try every ProxyJump entry in the file, and ask them in turn to resolve the name until you find one that works.
> This seems to be a misunderstanding: Yes, there would be a chicken-egg situation if the ProxyJump command would only know an unqualified hostname, like "blah" in your example. But that's not what I'm heading for
> ...
> there was no intent or reason to have an unqualified hostname in ProxyJump

Sorry, that bit was just my laziness in typing.  Pretend that I had written:

host *.example.com
     ProxyJump blah.some.random.domain

or

host *.example.com
     ProxyJump proxy.example.com

The argument would be the same.  If you try to ssh to an unqualified 
host like "foo", then you don't know that it might be resolvable via the 
given ProxyJump host until you first know that it matches *.example.com 
- a circular dependency.

Regards,

Brian.