BSS was Stalling due to DNS resolution

skb007 · Post by **skb007** » Thu Sep 19, 2019 10:03 am

1. Brekeke Product Name and Version:BSS Adv Ver 3.8

2. Java version:1.8

3. OS type and the version: RHEL 7.6

4. UA (phone), gateway or other hardware/software involved:NA

5. Your problem: BSS was trying to do DNS resolution and stalling because there is no internet access on the BSS server.

Customer sends the A-leg of call to BSS and BSS does a lookup using webget and BSS sends the B-lgb of call to provider. Webget request is sent to the local ip address of BSS itself. Everything was working well for well over a month. There is no change on the network, OS or BSS.

All of sudden we started seeing alarms that BSS stopped responding to SIP options. We logged into BSS and it was responding very slow. Status page was timing out. We restarted the BSS, it would come up and process few calls and freeze up again. We restarted the server and same thing.

Then we ran strace on the BSS process and found that BSS is reading /etc/resolve.conf and it is trying to resolve something and it was timing out because we don't have internet access on the BSS server. As soon as we commented both the name servers in /etc/resolve.conf and BSS started responding normal.

Incoming calls are coming in from an IP address, webget is done one the IP address , outbound calls are also going on the IP address. We don't use domain names anywhere so we don't know what is it that BSS was trying to resolve?

Any help would be much appreciated.

james · Post by **james** » Thu Sep 19, 2019 12:57 pm

Depends on license activation method, the BSS accesses to the Brekeke's License server over the Internet periodically.

FYI:
https://docs.brekeke.com/lic/online-act ... r-firewall
https://docs.brekeke.com/lic/online-activation
https://docs.brekeke.com/lic/what-is-th ... ctivations

Do you know which activation method you used for your product ID?

skb007 · Post by **skb007** » Fri Sep 20, 2019 12:08 pm

We used the offline activation method.

james · Post by **james** » Fri Sep 20, 2019 1:28 pm

Here are possibilities.
- DialPlan has a rule which points a FQDN.
- Received SIP packet has a header which indicates a FQDN.

If you review the log around when the issue happened, you might find some error messages related with DNS queries.

Are there any result if you execute "dnscache" command at [Tools]->[Command] page?
https://docs.brekeke.com/sip/dnscache

skb007 · Post by **skb007** » Fri Sep 20, 2019 2:00 pm

dnscache command did not produce any results.
No dial plan uses FQDN.
I am not sure about SIP header containing a FQDN.But even if SIP header was containing a FQDN why would it try to resolve it ?
I dont see any errors on the log file but I see the follwing errors:

sv.20190918.log:session.11406: java.lang.Exception: Parse Error "ACZQQLQOVJCFI4TUEV5RNIJ4ZNDLHBDWFYUXW4U4SOCRM4ACY44A2L7QKROQM6C:5060"
sv.20190918.log: java.lang.Exception: Parse Error "ACZQQLQOVJCFI4TUEV5RNIJ4ZNDLHBDWFYUXW4U4SOCRM4ACY44A2L7QKROQM6C:5060": (depth=7)

james · Post by **james** » Fri Sep 20, 2019 2:27 pm

> ACZQQLQOVJCFI4TUEV5RNIJ4ZNDLHBDWFYUXW4U4SOCRM4ACY44A2L7QKROQM6C:5060

It is what the SIP Server tried to resolve over DNS.
Can you find it in SIP headers? What kind of FQDN is it?

skb007 · Post by **skb007** » Mon Sep 23, 2019 10:50 am

I have turned on the SIP traces on the BSS and I will be able to see the complete SIP header when it happens next time.

In the mean time, is there any setting for BSS to disable the DNS resolution of SIP headers?

james · Post by **james** » Mon Sep 23, 2019 11:11 am

Set the line below at [Configuration]->[Advanced] page.
It will block all DNS queries.

Code: Select all

net.dns.filter.pattern = .*