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

[Rob Dawson]

We have an environment that consists of two PDNS servers that are using a MySQL backend.

Server A holds a PDNS instance and the MySQL master.
Server B holds a PDNS instance and the MySQL slave.
Each server is configured to use its local MySQL instance for the backend.

The primary use of these systems is to answer ENUM queries from our session border controllers for call routing decisions.

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.

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? 0.0.0.2.7.7.5.1.0.3.e164.arpa. (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)

Both of these behaviors seem a little odd to me, any thoughts?

Thanks,
Rob
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.powerdns.com/pipermail/pdns-users/attachments/20170901/9df8ac3f/attachment.html>