Tomas Korbar:
> Hi guys,
> I would like to start a discussion about support for SRV records, mainly
> record for submission service of a domain.
> As is stated in [0], domain can publish dns record, which tells services
> where the submission service of this domain is.
> This could be used for auto configuration of postfixs relayhost option.
> I used this patch [1] to make postfix 3.5.4 support resolving of this:
> "relayhost = [_submission._tcp.$mydomain]:587"
> as a valid host for submission of mail in my domain. This will allow users
> to automate their configurations a little more.
> I would like to know your opinion and whether this could be officially
> supported.
> Thanks for any help.
>
> [0] - https://tools.ietf.org/html/rfc6186#section-3
> [1] - https://tkorbar.fedorapeople.org/postfix-3.5.4-relayhost.patch
Is "_submission._tcp" special only in the SMTP client? What happens
with "_submission._tcp.$mydomain in other Postfix programs?
The patch changes the global proto_info structure. That is unnecessary,
and I have changed Postfix 3.6 to use "const INET_PROTO_INFO *"
pointers everywhere, to prevent such unnecessary changes in the future.
What is the difference in behavior between
[_submission._tcp.$mydomain]:587
and
_submission._tcp.$mydomain:587
What happens when DNS lookup is disabled (smtp_lookup = native)?
I suppose the same thing that happens in other Postfix programs?
Where is the documentation that describes how this works?
The SRV handler in libpostfix-dns should parse the entire record.
These questions may seem unhelpful, but the onus is not on me to
solve the problems when someone writes new code.
Wietse
