What port do web servers connect to DNS-Only DNS nameservers on?

[electric]

Hello,

I have a setup of four "DNS-Only" nameserver servers. (ns1/ns2/ns3/ns4.nameserver.com)

One of my web servers has recently started showing errors like this:

The following DNS cluster members are unreachable from my.webserver.com: [Note: I have changed the IP and server hostname for privacy.]

1.2.3.4

DNS commands for these servers are currently being queued.
If the DNS cluster members are unreachable because of a temporary
network outage the queued commands will be automatically processed when connectivity is reestablished.

To check the DNS cluster settings or disable this notification,
visit the "Configure Cluster" interface in WebHostManager.

https://ns4.nameserver.com:2087/cgi/clusterstatus.cgi

Event Log for 1.2.3.4:
WKTSOb0x3JFPBSgewLBn5fvGgMIWaULk 1.2.3.4 "QUICKZONEADD" [started: Tue Mar 25 08:34:01 2014] [ended: Tue Mar 25 08:34:36 2014] 0 Cpanel::NameServer::Remote::cPanel: Unable to Connection Timed Out [ns4.nameserver.com] (Timeout while connecting: Connection Timed Out)
---
WKTSOb0x3JFPBSgewLBn5fvGgMIWaULk 1.2.3.4 "QUICKZONEADD" [started: Tue Mar 25 08:49:01 2014] [ended: Tue Mar 25 08:49:36 2014] 0 Cpanel::NameServer::Remote::cPanel: Unable to Connection Timed Out [ns4.nameserver.com] (Timeout while connecting: Connection Timed Out)
---

.. and then this repeats about a dozen times.

One interesting thing is that when I login to the DNS-Only nameserver server and go to the "Home->Cluster/Remote Access->Configure Cluster" screen, I see a lot of connection errors.

Under the "Status" column, it says "Connection Timed Out" for about 1/2 the web servers that are configured to use this nameserver. The other 1/2 are not showing any errors.

Any ideas? Maybe it's some kind of connectivity issue? I tried pinging the nameserver in question from one of the servers that says it can't connect, and it works fine. Same if I try pinging the "can't connect" web server... it connects immediately.

Does anyone have any suggestions what might be the problem? I have tried disabling the nameserver's firewall (using CSF) and it makes no difference.

Thanks.

 

[robb3369]

The servers communicate over port 2087 (non-ssl uses 2086)... so in your main cpanel server, make sure the outbound port is open and the same port number for incoming on the dns only servers.

Here is a good doc for how clustering works
http://docs.cpanel.net/twiki/pub/Al...rainingSlides09/DNS_Cluster_Configuration.pdf

 

[cPanelMichael]

Hello

It seems like it might be a firewall issue with outgoing connections on the hosting machine if you have other hosting machines successfully connecting to that DNS-Only server.

Thank you.