Nagios Support Forum

I am setting the Nagios XI to monitor our systems but we are having issues with the configuration of the NCSA in order to monitor the infrastructure that is located outside the firewall using the passive mode.

The problem that we have is that the remote host cannot connect with our Nagios Server through the port TCP 5667.
I have tested from the Nagios server the NSCA service with the following results:
• ps aux | grep nsca Successful
• telnet localhost 5667 Successful
• telnet IpaddressEth0 5667 Successful
• netstat –lpn | fgrep :5667 Successful
• nmap -sS –O IpAddressEth0 The port 5667 is not open

When I try to telnet the port 5667 from other computer always the connection is refused.

This test I did from other computer in the same vlan to avoid firewall issues and also from other vlan and also from outside using the WAN network.

Honestly, I don’t know what can I try to resolve this issue so any help will be very helpful

Its so well written, so I'm just gonna snip the troubelshooting section off of http://nagios.sourceforge.net/download/ ... _Setup.pdf

1) Make sure the hostname defined in Nagios EXACTLY matches the hostname defined in your
packet sent INCLUDING upper/lower case.
2) Make sure the service description used in the packet sent EXACTLY matches the Nagios service
description, including case, embedded spaces, etc.
3) Check the NSCA log (syslog?) to make sure that the messages are being received by NSCA.
4) Check the nagios.log file to make sure they are being processed by Nagios. Have you enabled the
external command file?
5) Check the nagios.log file. Are the NSCA messages being ignored because you have the wrong
hostname or service description?
6) Check your filewall settings to allow 5667 (or other port as used)
7) If you have installed under xinetd, make sure you specify the IP address you are listening for, or
remove the “only_from” line in your xinetd’s nsca script.