Getting Data In

Do Splunk inputs dedicated to universal forwarders need reverse DNS configured?

vptltd
Engager

We have around 230 PCs servers spelunking to a single splunk server across a firewall.

Many of these clients are not logging data and show connection and timeout errors in splunkd log etc. After some research I have seen suggestions that incorrectly configured reverse DNS may be a cause.

Simple question is do the splunk inputs dedicated to universal forwarders need configuration regarding DNS? I thought that the hostname was provided by the splunk forwarder config files rather than DNS.

Am I confusing other inputs with which need this?
Any advice gratefully received.

Tags (2)
1 Solution

vptltd
Engager

Managed to resolve this with the help of tech support and solution is below in case others find it useful.

Reverse DNS lookups were indeed the issue. When creating the splunk forwarder input, the default "connection_host" (inputs.conf) is to use reverse dns. In our case no dns/access via firewall was possible to multiple timouts/net traffic generated which was stopping other clients connecting reliably.

Edited the input to "connection_host" to "none", restarted splunk and all was well with no further connection timeouts in splunkd.log etc.

View solution in original post

vptltd
Engager

Managed to resolve this with the help of tech support and solution is below in case others find it useful.

Reverse DNS lookups were indeed the issue. When creating the splunk forwarder input, the default "connection_host" (inputs.conf) is to use reverse dns. In our case no dns/access via firewall was possible to multiple timouts/net traffic generated which was stopping other clients connecting reliably.

Edited the input to "connection_host" to "none", restarted splunk and all was well with no further connection timeouts in splunkd.log etc.

Got questions? Get answers!

Join the Splunk Community Slack to learn, troubleshoot, and make connections with fellow Splunk practitioners in real time!

Meet up IRL or virtually!

Join Splunk User Groups to connect and learn in-person by region or remotely by topic or industry.

Get Updates on the Splunk Community!

Persistent Queue at TcpOut — One of Splunk's Most Practical Features

Splunk introduced persistent queueing at the tcpout layer as one of the most practical resilience features in ...

Skip the Awkward Silence: Have a .conf-ersation at .conf26

Picture this. You arrive at .conf26 already having your socializing and networking plans mapped out. No ...

Rethinking Zero Trust: From Product Purchases to Logical Control Evidence

Implementing Zero Trust (ZT) across complex environments often falters at the very beginning due to a ...