our isp not supports EDNS?

Anatoly Pugachev mator at team.co.ru
Tue Jun 22 15:58:14 UTC 2010


Mark,

please see below...

On 04.05.2010 / 14:31:25 +1000, Mark Andrews wrote:
> 
> In message <y2sf7e964441005031927m7774769ev280156817d8b4d53 at mail.gmail.com>, Je
> ff Pang writes:
> > Hello,
> > 
> > Following the discussions in the list, I made a test on one of our
> > servers, which is in an ISP's datacenter.
> > 
> > The result is below:
> > 
> > $ dig +short rs.dns-oarc.net txt
> > rst.x476.rs.dns-oarc.net.
> > rst.x485.x476.rs.dns-oarc.net.
> > rst.x490.x485.x476.rs.dns-oarc.net.
> > "218.204.255.72 DNS reply size limit is at least 490"
> > "218.204.255.72 lacks EDNS, defaults to 512"
> > "Tested at 2010-05-04 02:23:51 UTC"
> > 
> > Does this mean our ISP's filrewall block EDNS query/response?
> 
> Maybe / maybe not.  It could just mean that the nameserver itself
> doesn't support EDNS.

How bad it is, if providers server doesn't support/make eDNS queries?
Does eDNS support/usage is for DNSSEC protocol only? I mean, that my
collegue propose to use the following statement in named.conf:

server 0.0.0.0/0 {
        edns no;
};

in fix to the broken servers, which are doesn't support eDNS queries, for
example ns51 / ns52.domaincontrol.com ( which are hosting a lot of domains 
http://www.statsinfinity.com/ns_parent_zone_info/DOMAINCONTROL.COM and dig
+bufsize requests to them are ending with a timeout, so it probably just
firewall'ed for packets more than 512 bytes long). 






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