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i have to monitor some ports at a remote site.
Normally you can do this with check_tcp. Only incoming port 5666 is allowed at the remote site.
So I try to do this with nrpe:
I define a service at nagios-server
The check is working. But I see there's still traffic between nagios-server and client for port 2222.
Is there an explenation for ?
(At this moment I'm testing without a firewall.)
If there's no firewall, then why wouldn't you expect port 2222 to be open? check_tcp doesn't test if there's traffic going from the two servers, just that there could be. Are you using some other method to see traffic, like a tcpdump? I'm not familiar with anything on that port.
I am testing this at our infrastructure. Between the server and the client there is no firewall.
The client is running a service on port 2222. I am trying to check this by only using nrpe (port 5666). At the customers site I can only connect to 5666. They don't want to open other ports for the nagios connection.
I am using tcpdump.
[root@zabbix objects]# ../../libexec/check_nrpe -H 192.168.0.10 -c check_tcp_2222
TCP OK - 0.001 second response time on 127.0.0.1 port 2222|time=0.000717s;;;0.000000;10.000000
I see the following output from tcpdump (client):
[root@web01 etc]# tcpdump -i lo -nn port 2222
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on lo, link-type EN10MB (Ethernet), capture size 65535 bytes
It sounds like there could be another check that is defined on the Nagios server that could be checking for port 2222.
Make sure there is not another service check defined.
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