I’m new in Linux and basically I’m starting with it because I need a good monitoring tool for our network.
I installed Nagios already on a VM with Ubuntu and had no problem using it… then I installed it on a server with Debian 9 and again, had no problem at all.
But my boss wants a server with Fedora as OS, so now I installed Nagios on Fedora 9, and guess what… I have problems !
The installation happens problemless, and when I’m finished I can run Nagios from a browser on the server itself… but I can’t reach Nagios from any other remote host.
I checked everything and both server and client see each other, httpd service is running (there’s actually 9 of them constantly running, even after a reboot or when I restart the service myself).
I also noticed some SELinux thingy that seemed annoyed by my attempts on starting Nagios remotely, but even after I disabled the damn thing I still cannot consult Nagios from a remote computer.
I googled my problem of course but didn’t find anything like it… or perhaps I can’t formulate it right… anyway, I’m stuck and I would appreciate some help.
Thanks in advance,
Michel
EDIT : maybe something useful >> I followed the official installation guide from Nagios using nagios-3.0.5.tar.gz as source.
Have you got a firewall between client and server, either as an interim hardware device or perhaps software on the server (something like iptables)? What happens when you telnet to your nagios server on port 80?
This is what I get from a telnet on port 80 to the server :
[quote]Connecting To 172.20.40.157…Could not open connection to the host, on port 80:
Connect failed[/quote]
I’m not surprised, I don’t expect it to accept telnet connections on that port, actually, even on port 23 it refuses the connection, which I expect it to do…
What I authorise to this server, is a SSH connection on 22, and I expect it to accept connections on port 80 through the httpd service.
Now to answer the question, there is a firewall, but no restrictions on the LAN side… I also have Nagios installed on a Debian server, which I can connect right now next to the Fedora server, and I’m able to surf to its Nagios page. I also did exactly the same things on all 3 installations (Ubuntu-VM, Debian and Fedora), except for that SELinux disable part for Fedora, and have no problem at all on Ubuntu or Debian, so I’m thinking there is some extra protection I need to get passed in order to surf remotely to my Nagios main page.
Anyway, thanks already for replying I kept on searching since yesterday but still didn’t find anything yet, so I’ll be keeping this forum opened hoping for some more tries to find out a solution for my problem…
OK, so when you do a telnet <host>, yeah, you’re using port 23. When you telnet <host 80>, you are trying to access the server on port 80, the http port, not port 23 i.e. even if port 23 is blocked and/or firewalled, if port 80 is open you should be able to telnet to it through the LAN. It still sounds like you have the iptables firewall running to me… the default configuration is to allow anything on the loopback address, which would be why you can browse to the nagios webpages locally. Secondly, IIRC, the default is also to permit SSH sessions, so yeah, you’d still be able to SSH to your box even if the iptables firewall is running. And it allows ping requests, but sadly though that’s about all it allows…
See if you get anyt response from service iptables status or iptables --list… if it* is *running you will see the current firewall configuration and probably find that it has rules in it similar to how I described.
I kept on searching since yesterday but still didn’t find anything yet, so I’ll be keeping this forum opened hoping for some more tries to find out a solution for my problem…