Syslog Not Received on the LibreNMS Device

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1

Hi all,

I’m currently playing around with pre-packaged LibreNMS but I’m stuck on syslog with both rsyslog and syslog-ng not yielding results. I tried installing and configuring both syslog-ng and then rsyslog on all devices (Linux Server + Linux Client + Cisco Switch) but all I ever got are localhost syslog messages on LibreNMS. Even with tcpdump on port 514 nothing is shown.

I verified that the syslog on each device was working correctly and made sure that all configurations are correct. Syslog is enabled in config.php. I followed the documentation as closely as possible, making changes where needed.

What could be the problem that I might have missed?

2

Blocked by the firewall?

3

the firewall is disabled :frowning:

4

Selinux configured or disabled?

Or just paste your syslog config here. Is the daemon listening? (Output of “netstat -tulpen”)

5

Forr the SElinux i have cheched it it’s already disbled for the daemon there is no packets that are displayed .

6

What do you mean “there is no packets displayed”

7

when i put this command line tcpdump -i eth0 udp port 514 to listen to the traffic passing through the Rsyslog port,so i can see nothing

8

What’s the Output?

9

I just found out that on the LibreNMS server/device (a virtual machine), tcpdump only detects traffic initiated by the device itself but not others. For example, when I ping from LibreNMS to a device in the same network, tcpdump shows both echo request and reply. But if the ping is initiated from that other device, nothing is displayed (however all the ping and discovery between these devices work as usual). Could this be the problem?

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10

Sounds like a SELinux or Firewall issue.

Your output of netstat looks good so far.

11

You mean client side!
I believe I did check SELinux and Firewall last time and both were deactivated for both client device and LibreNMS. Could it be the network settings on the Virtualbox (which is set as NAT)?

12

Yes, NAT will not allow the packets through that direction without port forwarding. You need to change it to bridged if you want to use it like that or set up a port forwarding rule (bridged is better). The VM is set to NAT for easing evaluation.

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