[OpenSIPS-Users] DNS Cache module

[Ben Newlin]

Hello,

We use the DNS cache module to reduce the time spent querying DNS records. We recently had a customer call failing and we traced the failure to the customer using an FQDN in the Record-Route header. On the ACK, OpenSIPS appeared to not be able to resolve the domain even though it had been successfully resolved on the initial request. I found the log for the DNS Cache module and noticed that the value it was inserting was empty:

INFO:dns_cache:put_dnscache_value: putting key [dnscache_customer.domain.com_a] with value [] ttl = 60

This prompted me to examine all of our logs and I found that the value for these DNS Cache logs is always empty, regardless of the domain. It appears the records are not being serialized properly into the cache.

The DNS resolution must be succeeding or all of our requests using DNS would be failing, but I have also verified the domains all can be resolved manually on the same box:

$ nslookup customer.domain.com
Server:       10.27.0.2
Address:      10.27.0.2#53

Non-authoritative answer:
Name:  customer.domain.com
Address: 10.27.172.132
Name:  customer.domain.com
Address: 10.27.192.211
Name:  customer.domain.com
Address: 10.27.255.53

Any thoughts? Is there more information I can obtain to determine the cause?

Ben Newlin
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opensips.org/pipermail/users/attachments/20181206/3467b980/attachment.html>