can't monitor via web browser from remote pc

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hardstyle247
Posts: 1
Joined: Mon Dec 11, 2017 5:06 am

can't monitor via web browser from remote pc

Post by hardstyle247 »

Hello Nagios experts,

I am not completely new to Nagios but my Linux knowledge covers only the basics so far.
I am trying to set up a nagios core server on a Linux Virtual Machine (Centos 7, 192.168.122.124).
The pc I am running the Nagios Server VM on has got the IP address 10.0.12.33 (Debian 9). I installed virt-manager on it.
The virt-manager is configured with NAT.
I can monitor nagios from a web browser like firefox on BOTH debian9 (host) and centos7(guest)!

But I can't monitor via web browser from other pcs in my network. I would like to monitor from 10.0.10.25 (windows 7).
If i ping (from 10.0.10.25) 10.0.12.33, I can reach the host but by pinging 192.168.122.124 the guest cannot be found.
The error says: "response from 10.0.12.33: destination port unreachable."

10.0.12.33 is configured as the gateway for 192.168.122.124.

So apparently the gateway 10.0.12.33 can be found but from there 192.168.122.124 seems to block my pings?
I can ping successfully from 10.0.12.33 to 192.168.122.124 by the way.
Do I need to change my firewall/security settings so the guest 192.168.122.124 can be pinged from 10.0.10.25?

Overview:
win7-host: 10.0.10.25
subnet mask: 255.255.0.0
standard gateway: 10.0.18.1
dhcp-server: 10.0.10.120
dns-server: 10.0.10.120


vm-host(debian9): 10.0.12.33
enp6s0
inet 10.0.12.33/16 brd 10.0.255.255 scope global dynamic enp6s0
virbr0
inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
virbr0-nic
(shows MAC address only)
vnet0
(shows MAC address only)


nagios-vm(centos7): 192.168.122.124
eth0
inet 192.168.122.124/24 brd 192.168.122.255 scope global eth0
virbr0
inet 192.168.124.1/24 brd 192.168.124.255 scope global virbr0
virbr0-nic
(shows MAC address only)
gateway 10.0.12.33
dns 10.0.10.120, 8.8.8.8

Any help is highly appreciated!
bolson

Re: can't monitor via web browser from remote pc

Post by bolson »

Hello hardstyle247,

Clearly, if you can't ping 192.168.122.124 from 10.0.10.25 but you can ping 192.168.122.124 from 10.0.12.33 then it's very unlikely that this is a firewall issue. It's much more likely to be a routing issue. Please share your rationale for such a complicated networking scheme. Also this is so clearly not a Nagios issue in any way, you're probably not going to get much in the way of responses on this forum. That said, my advice for this issue (and troubleshooting in general) is to simplify your network as much as possible and then, once things are working, if you need to add complexity, add it in incrementally to see exactly where the the complexity breaks your network.
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