Could Not Ping host error

Brian_Gibson · 28 January 2019 21:03

Hi folks,

So I’ve tried searching through the previous posts for a relevant situation to mine. I do see several posts related to a could not ping message when trying to add a host. But they seem to be mostly about selinux.

I am running the base docker image. When I try to add a host from the CLI or GUI I get “could not ping”.

I am able to ping and do an snmpwalk from the docker shell.

Here is the validate,php output.

bash-4.4# ./validate.php

Component	Version
LibreNMS	1.47
DB Schema	275
PHP	7.2.13
MySQL	5.5.56-MariaDB
RRDTool	1.7.0
SNMP	NET-SNMP 5.7.3

====================================

[OK] Composer Version: 1.8.0
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct
[FAIL] The poller (8616b9cb2a58) has not completed within the last 5 minutes, check the cron job.
[FAIL] The poller (88ebe6420b94) has not completed within the last 5 minutes, check the cron job.
[FAIL] Discovery has never run. Check the cron job

Since I haven’t been able to ping anything I can’t start an autodiscovery.

I do a packet capture from the host OS on the docker interface and I don’t see any traffic coming out when I run ./addhost.

Thank you for any help.

murrant · 28 January 2019 21:19

It uses fping to check. Try running that to the host as the librenms user. (also check the validate page in the webui (it is run in the same way as addhost is in the webui).

Brian_Gibson · 28 January 2019 21:40

I get the following error when trying to run fping.

(null): can’t create raw socket (must run as root?) : Address family not supported by protocol.

I get this error whether running as root or librenms.

Brian_Gibson · 28 January 2019 22:27

I also get the same if I do fping -h.

Here are the file permissions…

-rwsr-xr-x 1 root root 39600 May 1 2018 fping

Seems fine. I assume setuid being set is right?

Brian_Gibson · 28 January 2019 23:50

So I tried using Jaris Schaefer’s docker as well. Same problem. However I did have a problem with his docker that nginix started up trying to bind to an ipv6 which I don’t have configured on this host or container.

So I’m guessing that might be the problem here.

Reading this, it looks like there was an issue with fping…

github.com/schweikert/fping

fping when ipv6 is disabled on a server

opened 05:09AM - 12 Jul 17 UTC

closed 06:05AM - 29 Jul 18 UTC

pezz

Hi there, I was just curious if fping is working as intended when ipv6 is dis…abled on a box? I get some very strange behaviour: ``` % fping -4 www.google.com (null): can't create raw socket (must run as root?) : Address family not supported by protocol % sudo fping -4 www.google.com (null): can't create raw socket (must run as root?) : Address family not supported by protocol % ls -al /usr/bin/fping -r-sr-xr-x 1 root root 47796 Apr 29 03:28 /usr/bin/fping % pacman -Qs fping local/fping 4.0-1 A utility to ping multiple hosts at once % fping -h (null): can't create raw socket (must run as root?) : Address family not supported by protocol % sudo fping -h (null): can't create raw socket (must run as root?) : Address family not supported by protocol ``` I can't even print the help page. This is on Arch Linux ARM and is built with the options contained in this PKGBUILD: https://archlinuxarm.org/packages/armv7h/fping/files/PKGBUILD Any thoughts? Cheers.

Brian_Gibson · 30 January 2019 17:09

So I spun up a generic Alpine image and installed fping on that. Same problem.

Now it’s time for me to see if I can get an IPV6 address configured on my vm host.

Brian_Gibson · 30 January 2019 18:08

So that fixed this issue.

So to be clear. Whether you use IPV6 or not, you must have a IPV6 IP address configured on your host machine and allow the container to see otherwise fping will not work properly.