Weird ifDescr caused by weird SNMP

[marklittle]

Hey there,

So I have been debugging a weird graph title issue which I thought initially was because of an update of Cacti I did. I figured it reset the max length for the graph title's - but it didn't.. I was still getting weird content within the graph title from a IBM Blade Chassis NIC.

I finally tracked it down that when I do a verbose query under 'SNMP - Interface Statistics', I can see the problem.. For those Blade NIC module, I see:

+ Executing SNMP walk for data @ '.1.3.6.1.2.1.2.2.1.2'
+ Found item [ifDescr='External Port 4'] index: 1 [from value]
+ Found item [ifDescr='External Port 4'] index: 2 [from value]
+ Found item [ifDescr='External Port 4'] index: 3 [from value]
+ Found item [ifDescr='External Port 4'] index: 4 [from value]
+ Found item [ifDescr='External Port 4'] index: 5 [from value]
+ Found item [ifDescr='External Port 4'] index: 6 [from value]
+ Found item [ifDescr='External Port 4'] index: 7 [from value]
+ Found item [ifDescr='External Port 4'] index: 8 [from value]
+ Found item [ifDescr='External Port 4'] index: 9 [from value]
+ Found item [ifDescr='External Port 4'] index: 10 [from value]
+ Found item [ifDescr='External Port 4'] index: 11 [from value]
+ Found item [ifDescr='External Port 4'] index: 12 [from value]
+ Found item [ifDescr='External Port 4'] index: 13 [from value]
+ Found item [ifDescr='External Port 4'] index: 14 [from value]
+ Found item [ifDescr='45:78:74:65:72:6E:61:6C:20:50:6F:72:74:20:34:00:00'] index: 15 [from value]
+ Found item [ifDescr='45:78:74:65:72:6E:61:6C:20:50:6F:72:74:20:34:00:00'] index: 16 [from value]
+ Found item [ifDescr='External Port 4'] index: 17 [from value]
+ Found item [ifDescr='External Port 4'] index: 18 [from value]
+ Found item [ifDescr='External Port 4'] index: 19 [from value]
+ Found item [ifDescr='External Port 4'] index: 20 [from value]

and this is what is causing the issue. If I individually snmpget those OIDs I get:
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw' bl1-nic1 .1.3.6.1.2.1.2.2.1.2.17
.1.3.6.1.2.1.2.2.1.2.17 = STRING: "External Port 1"
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw' bl1-nic1 .1.3.6.1.2.1.2.2.1.2.12
.1.3.6.1.2.1.2.2.1.2.12 = STRING: "Physical Port 12"
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw' bl1-nic1 .1.3.6.1.2.1.2.2.1.2.11
.1.3.6.1.2.1.2.2.1.2.11 = STRING: "Physical Port 11"
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw bl1-nic1 .1.3.6.1.2.1.2.2.1.2.16
.1.3.6.1.2.1.2.2.1.2.16 = STRING: "Management Port 2"
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw' bl1-nic1 .1.3.6.1.2.1.2.2.1.2.17
.1.3.6.1.2.1.2.2.1.2.17 = STRING: "External Port 1"
[root@kh-mon1:~]# /usr/bin/snmpget -On -v2c -c 'pw' bl1-nic1 .1.3.6.1.2.1.2.2.1.2.19
.1.3.6.1.2.1.2.2.1.2.19 = STRING: "External Port 3"

but it seems when Cacti does it, it is doing an snmp bulkwalk.. and it is being returned bogus data. I was able to reproduce this like so:


[root@kh-mon1:~]# snmpbulkwalk -c <pw> -v2c bl1-nic1 .1.3.6.1.2.1.2.2.1.2
iso.3.6.1.2.1.2.2.1.2.1 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.2 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.3 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.4 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.5 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.6 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.7 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.8 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.9 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.10 = STRING: "Physical Port 10"
iso.3.6.1.2.1.2.2.1.2.11 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
iso.3.6.1.2.1.2.2.1.2.12 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
iso.3.6.1.2.1.2.2.1.2.13 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
iso.3.6.1.2.1.2.2.1.2.14 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
iso.3.6.1.2.1.2.2.1.2.15 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
00
iso.3.6.1.2.1.2.2.1.2.16 = Hex-STRING: 45 78 74 65 72 6E 61 6C 20 50 6F 72 74 20 34 00
00
iso.3.6.1.2.1.2.2.1.2.17 = STRING: "External Port 4"
iso.3.6.1.2.1.2.2.1.2.18 = STRING: "External Port 4"
iso.3.6.1.2.1.2.2.1.2.19 = STRING: "External Port 4"
iso.3.6.1.2.1.2.2.1.2.20 = STRING: "External Port 4"
iso.3.6.1.2.1.2.2.1.2.256 = STRING: "DEFAUL"
iso.3.6.1.2.1.2.2.1.2.1025 = STRING: "DEFAULT_VLAN"

However I found that if I include the '-Cr1' option that I saw on this forum, it works...

[root@kh-mon1:~]# snmpbulkwalk -c <pw> -Cr1 -v2c bl1-nic1 .1.3.6.1.2.1.2.2.1.2
iso.3.6.1.2.1.2.2.1.2.1 = STRING: "Physical Port 1"
iso.3.6.1.2.1.2.2.1.2.2 = STRING: "Physical Port 2"
iso.3.6.1.2.1.2.2.1.2.3 = STRING: "Physical Port 3"
iso.3.6.1.2.1.2.2.1.2.4 = STRING: "Physical Port 4"
iso.3.6.1.2.1.2.2.1.2.5 = STRING: "Physical Port 5"
iso.3.6.1.2.1.2.2.1.2.6 = STRING: "Physical Port 6"
iso.3.6.1.2.1.2.2.1.2.7 = STRING: "Physical Port 7"
iso.3.6.1.2.1.2.2.1.2.8 = STRING: "Physical Port 8"
iso.3.6.1.2.1.2.2.1.2.9 = STRING: "Physical Port 9"
iso.3.6.1.2.1.2.2.1.2.10 = STRING: "Physical Port 10"
iso.3.6.1.2.1.2.2.1.2.11 = STRING: "Physical Port 11"
iso.3.6.1.2.1.2.2.1.2.12 = STRING: "Physical Port 12"
iso.3.6.1.2.1.2.2.1.2.13 = STRING: "Physical Port 13"
iso.3.6.1.2.1.2.2.1.2.14 = STRING: "Physical Port 14"
iso.3.6.1.2.1.2.2.1.2.15 = STRING: "Management Port 1"
iso.3.6.1.2.1.2.2.1.2.16 = STRING: "Management Port 2"
iso.3.6.1.2.1.2.2.1.2.17 = STRING: "External Port 1"
iso.3.6.1.2.1.2.2.1.2.18 = STRING: "External Port 2"
iso.3.6.1.2.1.2.2.1.2.19 = STRING: "External Port 3"
iso.3.6.1.2.1.2.2.1.2.20 = STRING: "External Port 4"
iso.3.6.1.2.1.2.2.1.2.256 = STRING: "System"
iso.3.6.1.2.1.2.2.1.2.1025 = STRING: "DEFAULT_VLAN"
[root@kh-mon1:~]#

So my first question is - is this a device SNMP bug, or somehow my monitoring station is causing this? and.. is there a way I can modify Cacti to always do '-Cr1' on snmp bulkwalk's? I have already set Max OIDs per request to 1 for the host and the default.

Your help is appreciated.

Thanks,
Mark