[dns-operations] too many round robin RR's / tcp and lookup errors?

Mark Jeftovic markjr at easydns.com
Sun Sep 16 01:41:09 UTC 2012

Wondering if this is "well known" or not.

We had a problem with a customer domain, for some reason it appeared as
though mobile devices on the Wind network couldn't resolve a domain.

Then I could duplicate the problem on the rogers network.

I realized that the hostname in question was using round robin DNS, and
had enough records that the response size was over 512 bytes, thus the
truncate bit was set and the resolver is supposed to retry over TCP.

So we had them drop enough records to get the response under 512 bytes
and the problem went away.

The questions I have are is this something with specific resolvers?
(Can't handle edns truncate and TCP retries properly) - but then we'd
expect to see this on regular web browsers too. We didn't that I'm aware
of, it was all mobile devices.

So is there something in iOS and possibly other mobile devices that
can't handle a TCP response, or can't handle a TCP response over 512
bytes or something else?

Anybody else run across this sort of thing?


Mark Jeftovic, Founder & CEO, easyDNS Technologies Inc.
Company Website: http://easydns.com
Read My Blog:    http://markable.com
+1-416-535-8672 ext 225

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