[Pdns-users] Couple of (maybe) oddities . . .

bert hubert bert.hubert at powerdns.com
Fri Sep 1 13:54:05 UTC 2017

On Fri, Sep 01, 2017 at 01:13:32PM +0000, Rob Dawson wrote:
> First Oddity - For each inbound call, the active SBC sends a query to both
> servers simultaneously.  I can see the queries hitting port 53 via
> tcpdump, the odd thing is that only one server will send a reply i.e.  if
> server A replies, server B does not and vice versa.  This is causing the
> SBC some concern and it is alarming that an ENUM server is out of service.

Please double check the queries are arriving on both servers. What we have
seen in production is mediocre firewalls getting confused keeping track of
multiple identical questions.

> Second Oddity –
> Whichever server replies, appears to be sending 3 responses. See below:
> 22:40:00.778687 IP X.X.X.X.blackjack > BS-VM-M75-1.domain:  13136+ NAPTR? (47)
> 22:40:00.779173 IP BS-VM-M75-1.domain > X.X.X.X.blackjack:  13136* 1/0/0 (107)
> 22:40:00.779177 IP BS-VM-M75-1.domain > X.X.X.X.blackjack:  13136* 1/0/0 (107)
> 22:40:00.779178 IP BS-VM-M75-1.domain > X.X.X.X.blackjack:  13136* 1/0/0 (107)

Again, measure on server A and B directly if you haven't yet. This behaviour
again correlates with a bad firewall if you are measuring on the SBC side.


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