Angel Gabriel wrote:
First off, I would like to say, dnsmasq, is an excellent piece of
software! Exceptionally fast, and right now, is serving close to 1000
clients over four subnets, who surf the internet as if their lives
depend on it.
I have only one problem. I have a postfix server, which is using
dnsmasq as it's DNS server. The problem is, it doesn't seem to be
returning any MX records. when I use the command line at any of my
terminals, and issue dig website.com I don't get any MX information.
Is there any reason for this behavior? This means that sometimes I
have hundreds of mails being defered on our mail server.
How can I configure dnsmasq to return MX data that it finds upstream?
There is no configuration required. When it gets a DNS query, dnsmasq
does one of two things: if it knows the answers to all the questions in
the query (because they're in /etc/hosts, /etc/dnsmasq.conf, or the
cache) then is creates an answer and sends it back. If dnsmasq can't
answer all the questions in the query, dnsmasq sends the query, almost
unmodified, to an upstream server. When the answer comes back, it
returns it, again almost unmodified, to the original requestor.
Because it's forwarding whole DNS requests, it doesn't matter they are
for RR types or operations which dnsmasq doesn't support. If dnsmasq
doesn't understand a query, it just forwards it. Thus, any DNS feature
works with dnsmasq's forwarding.
MX records don't completely fall into the category of things which
dnsmasq doesn't understand. It is possible to give the answers to MX
queries in /etc/dnsmasq.conf and have those returned. However if that's
not configured, or the query is for an MX record which dnsmasq doesn't
know about, then the same thing applies: the query will just be
forwarded, and whatever answer is coming back is coming from an upstream
server.
So in this case, first try running the dig command on your upstream
server(s) (all of them if there's more than one.) My guess is that the
problem is there. If not, check your dnsmasq config for mx-host,
mx-target, selfmx and localmx lines. You might be overriding the
upstream records with local configuration. To just get MX records from
upstream, you don't need any MX config at all in dnsmasq.
HTH
Simon.
