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SNMP Not working as it should

#1
(This post was last modified: 06/09/2017, 07:54 by tdale.)

Hello all,

I started this conversation on IRC and decided to bring it to the forum. I have a brand new installed VyOS box and im getting some odd SNMP results.

We are running VyOS 1.1.7

Here is the type of behavior we are seeing:

[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
SNMPv2-SMI::mib-2 = NULL
Error: OID not increasing: SNMPv2-SMI::mib-2
>= SNMPv2-SMI::mib-2

[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
Timeout: No Response from Interface-IP
You have new mail in /var/spool/mail/root
[root@web1 /]# snmpwalk -v 2c -c pubic Interface-IP
SNMPv2-SMI::mib-2 = NULL
Error: OID not increasing: SNMPv2-SMI::mib-2
>= SNMPv2-SMI::mib-2

[root@web1 /]# snmpwalk -v 2c -c pubic -Cc Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic -Cc Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic -Cc Interface-IP
Timeout: No Response from Interface-IP
[root@web1 /]# snmpwalk -v 2c -c pubic -Cc Interface-IP
SNMPv2-SMI::mib-2 = NULL
SNMPv2-SMI::mib-2 = NULL
SNMPv2-SMI::mib-2 = NULL
SNMPv2-SMI::mib-2 = NULL
SNMPv2-SMI::mib-2 = NULL
Timeout: No Response from Interface-IP

We have tried multiple interfaces ips as well. same result for any of them.


In the snmp log i see the following:

Sep  5 21:51:29 vyos snmpd[5366]: snmp_build: unknown failure
Sep  5 21:51:29 vyos snmpd[5366]: send response: Error building ASN.1 representation (wrong type in snmp_realloc_rbuild_var_op: 199)
Sep  5 21:51:29 vyos snmpd[5366]:     -- IF-MIB::ifName.1
Sep  5 21:52:29 vyos snmpd[5366]: last message repeated 2 times

When i try to snmpwalk it times out most of the time. Maybe 1 in 10 spammed snmpwalk actually returns data.

I did a ps aux | grep snmpd and it looks like this:

snmp     16679  0.5  0.0  55324  6952 ?        D    Sep05   0:59 /usr/sbin/snmpd -LSid -Lf /dev/null -u snmp -g snmp -p /var/run/snmpd.pid


This box has 8 10G SFP+ ports (intel 82599EB) and 4 1g sfp ports (intel 82576) 2 6 core cpus with HT (24 threads) and 48gb of ram.

Free -m : 

             total       used       free     shared    buffers     cached
Mem:         48300       1922      46378          0        146        115
-/+ buffers/cache:       1660      46640
Swap:            0          0          0


Top:

top - 01:17:39 up 2 days, 10:53,  3 users,  load average: 1.67, 1.71, 1.69
Tasks: 210 total,   1 running, 207 sleeping,   2 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni, 99.8%id,  0.2%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  49459580k total,  1968800k used, 47490780k free,   149932k buffers
Swap:        0k total,        0k used,        0k free,   118176k cached


Currently connected to the box is 1 10g SFP+ and 2 1g SFP connections. We are running BGP, we have 2 ISPs delivering full routes. We are not using any firewall or anything. The only thing that has been configured on this box is BGP, Interfaces, SSH and SNMP. Everything else is at default. I don't see any other real issues with it either.

Any help is greatly appreciated!!

Something else i noticed if i sudo killall -9 snmpd the load dies off as well.

top - 01:54:17 up 2 days, 15:29, 2 users, load average: 0.04, 0.31, 0.89
Tasks: 204 total, 2 running, 202 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.1%us, 0.0%sy, 0.0%ni, 99.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 49459580k total, 1975084k used, 47484496k free, 152928k buffers
Swap: 0k total, 0k used, 0k free, 133748k cached


Thanks,

Tom
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#2

Hey tdale.

I'm afraid I can't easily reproduce the problem - that's rather bigger gear and I don't have any 10G NICs that are free to put into Vyos test boxes, let alone a couple of full BGP feeds to point at 'em ;)

That being said...

22:57:52 ‹Jules_T› tdale - Not a particular area of my expertise... but a little google-fu...
22:58:24 ‹Jules_T› ... and this looks to be a known issue with 82599EB NIC cards.
22:58:33 ‹Jules_T› Or at least... it looks similar.
22:58:50 ‹Jules_T› https://phabricator.vyos.net/T17
22:59:27 ‹Jules_T› ... look down the channel... and I think you can apply patched versions of net-snmp.
22:59:36 ‹Jules_T› Sorry... look down the thead, I mean.
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#3

Unfortunately my issue is different than these. I can barely get snmp to give an output let alone query a interface..
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#4

Created https://phabricator.vyos.net/T397
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