[dnsdist] max packet size settings?

Brooks Bridges bbridges at o1.com
Sat Nov 19 16:57:21 UTC 2016

We are using dnsdist-1.1.0-0.1.beta1.1pdns.el6.x86_64 from the yum repo

I will gather the requested traces and packet captures a bit later this morning and send it to you directly, as it will contain sensitive information that is difficult to sanitize enough to post publicly.

Thank you for your prompt response!

Brooks Bridges | Sr. Voice Services Engineer
O1 Communications
5190 Golden Foothill Pkwy
El Dorado Hills, CA 95762
office: 916.235.2097 | main: 888.444.1111, Option 2
email: bbridges at o1.com | web: www.o1.com

From: dnsdist [dnsdist-bounces at mailman.powerdns.com] on behalf of Remi Gacogne [remi.gacogne at powerdns.com]
Sent: Saturday, November 19, 2016 12:03 AM
To: dnsdist at mailman.powerdns.com
Subject: Re: [dnsdist] max packet size settings?

Hi Brooks,

On 11/18/2016 10:21 PM, Brooks Bridges wrote:
> I am currently trying to utilize dnsdist as a load balancer in front of
> multiple pdns servers with a custom backend module that we are using for
> lcr purposes.  I am running into issues where if the response packet
> from the pdns server is above a certain size, dnsdist appears to just
> drop all data, and responds with an empty reply to the requesting side.
> We are using a max packet size of 1400 on the requesting client side and
> that seems to work just fine when we query against the pdns server
> directly, however once I wedge dnsdist in the middle, it all goes to
> crap as soon as we hit about 600-750 bytes.

dnsdist should have not trouble handling responses up to 4096 bytes.
What version of dnsdist are you using? Would you mind providing a trace
showing the query and request on both sides of dnsdist, preferably as a


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