Monitoring showing routers at down when they are up

[FlyingDuffman]

I've got two routers that are showing up under the Monitor tab that appear as being down, but when I click on them, it shows SNMP information and the graphs for these routers are being updated. I am able to get a response from these routers when I ping them as well (under the downed host detection setting I have selected Ping and SNMP).

Any idea what is going on?

[youri]

Hi

I got the same on a pix router (which discard udp "ping" packet.. ).
I can't have hime accept theses packets, and I can read the snmp answer when I create the device..
The host stays down , and never graph anything..(I don't want to change the check ping type..)

[FlyingDuffman]

My Pix are down too, but I think that's because I don't have SNMP turned on with them and because they won't return pings.

SNMP is definately turned on with the routers and it I ping them too... and they graphs for them are being created... why do they keep showing up as being down, Cacti doesn't seem to have any issues accessing them? They are both Cisco 2800 series routers.

[gandalf]

SNMP data is usually retrieved on port 161. If this works for your target, you will see some snmp information about this host on the Device Edit screen.

But "Downed Host Detection" does its own tests.
ICMP Tests need root access (at least on linux)
UDP Tests use port 33439

If you use UDP Ping Tests, this will poll for 33439 and may fail, if this port is blocked. So the host may be reported as down while it is able to access UDP port 161 for snmp.

Changing "Downed Host Detection" to SNMP should resolve this problem (for this host. But it may introduce other problems in your special installation), because you would use both SNMP via UDP for "Downed Host Detection" and for data retrieval.

Reinhard

[FlyingDuffman]

Ah...

Is there a way to make it so that Cacti will show a host as up if they respond to either a ping or an SNMP request? From what I you are saying, it appears right now they will have to respond to BOTH for them to show as up and a number of my servers aren't going to respond to pings, but I have some other hardward that doesn't have SNMP running.

The easy solution is if Cacti can do it, the harder solution is if I must either allow pings or setup SNMP on these different computers.

[gandalf]

Ah...

Is there a way to make it so that Cacti will show a host as up if they respond to either a ping or an SNMP request

This should be default behaviour of cacti 0.8.6i. Switch poller debug level to DEBUG for one polling cycle and look at log/cacti.log. You will see the results of downed host detection there
Reinhard