snmpwalk "timeout: No Response from localhost:1161" using net-snmp-5.4.3

khung · 08-28-2014, 01:08 AM

I'm new to Linux. I'm writing an SNMP extension agent using the MIB for Dummies (http://www.net-snmp.org/wiki/index.php/MIB_for_Dummies) config file (mib2c.mfd.conf). I successfully created my executable, adeSensorsTable, using my adeSensorsTable.MIB (mib2c util auto-generated the C source code from adeSensorsTable.MIB which I compiled into an executable). I then ran my executable:

./adeSensorsTable -f -L -DadeSensorsTable -M localhost:1161

I'd have a warning as I single stepped through the code:

iquerySecName has not been configured - internal queries will fail
Warning: no access control information configured.
(Config search path: /etc/snmp:/usr/share/snmp:/usr/lib/snmp:/home/ken/.snmp)
It's unlikely this agent can serve any useful purpose in this state.
Run "snmpconf -g basic_setup" to help you configure the adeSensorsTable.conf file for this agent.
[init_smux] bind failed: Permission denied

On a separate terminal I ran:
snmpwalk -v 1 -c public localhost:1161

MyOwnTable terminal would return:
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]
Connection from UDP: [127.0.0.1]:52684->[127.0.0.1]

My snmpwalk terminal would return:
Timeout: No Response from localhost:1161

I'm not sure if snmp extension agent's warning is the show stopper in this case. I'd appreciate if someone could provide some pointers to my timeout issue. Thank you in advance!

ferrari · 09-01-2014, 08:55 PM

Are you sure you're interrogating the correct port? What happens if you don't specify a port?

Code:

snmpwalk -v 1 -c public localhost

What does the following return about snmp-net (if anything?

Code:

nmap localhost

Perhaps these too...

Code:

lsof -Pni | grep snmpd

Code:

lsof -i tcp:1161

khung · 09-02-2014, 01:44 AM

Ferrari,

Thank you for your correspondence. If I ran "snmpwalk -v 1 -c public localhost" I'd get pages of responses back. This is just the first few lines of the responses:

SNMPv2-MIB::sysDescr.0 = STRING: Linux ken-Extensa-5620 3.2.0-67-generic #101-Ubuntu SMP Tue Jul 15 17:45:51 UTC 2014 i686
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (21084) 0:03:30.84
SNMPv2-MIB::sysContact.0 = STRING: G. S. Marzot <gmarzot@marzot.net>
SNMPv2-MIB::sysName.0 = STRING: ken-Extensa-5620
SNMPv2-MIB::sysLocation.0 = STRING: Unknown
SNMPv2-MIB::sysORLastChange.0 = Timeticks: (1) 0:00:00.01

"nmap localhost" returns:

Starting Nmap 5.21 ( http://nmap.org ) at 2014-09-01 23:24 PDT

Nmap scan report for localhost (127.0.0.1)
Host is up (0.000012s latency).
Not shown: 997 closed ports
PORT STATE SERVICE
53/tcp open domain
199/tcp open smux
631/tcp open ipp
Nmap done: 1 IP address (1 host up) scanned in 0.10 seconds

"lsof -Pni | grep snmpd" returns:

snmpd 14468 snmp 7u IPv4 607609 0t0 UDP 127.0.0.1:161

"lsof -i tcp:1161" returns nothing but

"lsof -i udp:1161" returns my snmp extension agent adeSensorsTable:

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
adeSensor 15153 root 5u IPv4 623703 0t0 UDP localhost:1161

I think the name adeSensorsTable was truncated on the previous line.

I then tried to use snmpget to reach one of my extension agent objects:

snmptranslate -On xxxxx-MIB::adeSensorsTable.aDESensorsEntry.vrms
and got:

.1.3.6.1.4.1.43905.1.1.1.1.2

then I ran:

snmpget -v 1 -c public localhost:1161 .1.3.6.1.4.1.43905.1.1.1.1.2

I'd get the same response:

Connection from UDP: [127.0.0.1]:55176->[127.0.0.1]
Connection from UDP: [127.0.0.1]:55176->[127.0.0.1]
Connection from UDP: [127.0.0.1]:55176->[127.0.0.1]
Connection from UDP: [127.0.0.1]:55176->[127.0.0.1]
Connection from UDP: [127.0.0.1]:55176->[127.0.0.1]

from adeSensorsTable executable.

I'm stumped here!

ferrari · 09-02-2014, 03:34 AM

I confess I'm way over my head on this, and while I have a basic understanding of SNMP, I don't really understand what you're trying to do here. In any case, the error you first reported regarding 'iquerySecName' (and maybe other config issues too) need to be addressed first. Therefore I'm going to point you at the snmpd.conf manpage.

http://www.net-snmp.org/docs/man/snmpd.conf.html

Enjoy!

khung · 09-02-2014, 11:54 AM

Ferrari, the SNMP commands I ran was just try to validate that the connectivity wasn't there. You can ignore that. I agree with you that resolving the iquerySecName is the main issue. I've looked the man page before and there was not much of an explanation what is iquerySecName and how to use it. I don't understand how to construct this iquerySecName properly. Any help is appreciated!

ferrari · 09-02-2014, 03:06 PM

Well, I've never had to configure snmpd.conf before, but from what I can gleam from a bit of googling, iquerySecName is used to specify the username for internal SNMP queries, and this name must first be explicitly defined with createUser first. Any access rights are defined by rouser.

Code:

createUser <internalname> MD5 "internal monitor"
iquerySecName <internalname>
rouser _internal noauth>

Maybe if you look at some sample snmpd.conf files (a few I've linked to below), it will help to get an idea on producing a working configuration

http://serverfault.com/questions/248...for-disk-usage
http://dev.miteric.com/2008/12/net-s...-settings.html
http://www.adventuresinoss.com/?p=1220
http://blog.tersmitten.nl/how-to-get...ntu-12-04.html

That's the best that I can do.