Re: [exim] MX name with _ : all relevant MX records point to…

mbneto wrote:

> Some clever admin configured the MX of a domain pointing to
> server_01.domain.com.

Never ever use other people's domain names for examples. That's what
example.{com,net,org} is for.
And if you want help on this mailing list, don't obfuscate things (apart
from passwords). This is both well explained in the mailing list etiquette.

Ok, now to the issue. Underscore in host names is quite common in the
windows world. But most of that poeple with internet connectivity
learned that it's better not to use it, because many people will not be
able to reach you because many software blocks _ in host names.
If you are more interested in operability than than compliance to
arbitrary decisions, you can allow it in Exim by overriding
dns_check_names_pattern in the config's main section. The default is, as
stated in the spec:

(?i)^(?>(?(1)\.|())[^\W_](?>[a-z0-9/-]*[^\W_])?)+$

The regex is probably not easy to understand (took me also a while). It
should be ok to add the _ in the middle list:

(?i)^(?>(?(1)\.|())[^\W_](?>[a-z0-9/-_]*[^\W_])?)+$



PS: I'm a little embarrassed by my list fellows. 7 replies, but no
solution, that's not something I would have expected...