name server on alternate port

Mark admin at
Mon Nov 24 19:54:53 PST 2003

----- Original Message ----- 
From: "Matthew Seaman" <m.seaman at>
To: "Mark" <admin at>
Cc: <freebsd-questions at>
Sent: Saturday, November 22, 2003 3:20 PM
Subject: Re: name server on alternate port

On Sat, Nov 22, 2003 at 01:55:01PM +0000, Mark wrote:

> If I want to install a second name server, on a different listening
> port, how can I get the resolver libraries to consult the other port
> too? I want to add rbldsnd, next to bind, for a large zone.

> I don't think that's really going to work. You can configure a slave
> server to do domain transfers on alternate ports, but that's about it.
> Everything else expects DNS servers to answer on port 53. You'ld be
> better off adding an alias address to the server and making each server
> bind each to it's own address.  Don't know about rbldnsd(8), but for
> bind9 you can put entries like this within the options{} section of
> named.conf:
>     listen-on {
>     };
>     query-source    address port 53;
>     transfer-source port 53;
>     notify-source port 53;

Thank you. :) Your idea to bind both nameservers on their own IP, with
rbldnsd on the alias, worked brilliantly well. Instead of configuring a
slave server, though, I went with forwarding, like so:

zone "" IN {
 type forward;
 forward only;
 forwarders {;

And now everything works beautifully. :)

- Mark

P.S. Getting rbldnsd to work was worth the trouble. I have the entire
dynablock, blackholes, and proxies zones, from the soon to expire
RBLs, all loaded in under 22 MB! of memory (and rbldnsd keeps everything in
memory too, in case you wondered). The same cost BIND over 220 MB memory!

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