[server-admins] Reverse DNS (and mailman, and iptables??)

[Jonathan Marsden]

Troy,

On 01/23/2011 09:37 PM, Jonathan Marsden wrote:

> So, let's just go for it, we can't break anything, since there is
> nothing in place now (for crosswire.org reverse DNS) to break :)

OK, I've now set up RFC4183-style reverse DNS on both crosswire.org and
codns.computeroptions.net -- and it appears to actually work (!).

So, once the delegation from the ISP takes effect, that should be taken
care of (BUT see below).  In other words, I can now do:

  dig @crosswire.org 106.104-29.190.71.64.in-addr.arpa. ptr +short

on crosswire.org and get the right answer back.

IMPORTANT: ARE WE BLOCKING DNS TRAFFIC TO THE SERVER?

I can't get DNS info from the crosswire.org server anywhere else.  I
suspect you may be running an iptables firewall that is blocking some
traffic?  Can you check this please?  TCP and UDP ports 53 need to allow
all inbound traffic on crosswire.org.

To check this, compare:

  dig @crosswire.org 106.104-29.190.71.64.in-addr.arpa. ptr +short

with

  dig @codns.computeroptions.net crosswire.org
106.104-29.190.71.64.in-addr.arpa. ptr +short

when each is run from some other machine somewhere.  Same issue for

  dig @crosswire.org crosswire.org a +short

and

  dig @codns.computeroptions.net crosswire.org a +short

Thanks,

Jonathan