snmpwalk parameters

['chris']

hi

on my Debian Sarge Stable I cannot do:

# snmpwalk 192.168.0.3 public

this command was working in the older versions of linux

but if I put some options:

snmpwalk -sO -c public -v 1 192.168.0.3

it seems to work.
knows someone why ?

and what mean exactly these options:

-sO -c -v 1 ?

kind regards
chris

[Rick Garland · Accepted solution]

The -c option you provide a community string. By default this is 'public'. If a system has a different get-community you can substitute here.

The -v 1 says you are using version 1 of the snmp utility.

The -sO I am not sure. I see a -0s which means to retrive all the variables under system OID (object identifier):

sysDescr.0
sysObjectID.0
sysUpTime.0
sysContact.0
sysName.0
sysLocation.0
sysServices.0

[Stuart Browne]

Are you sure it's '-sO' and not '-Os' ? '-Os' (which is more expected) just shows the last portion of the OID, just to make it easier to read.

As for the others... '-c' is the community to query.

'-v 1' says to use SNMP version 1 protocol.

What does 'snmpwalk -v1 192.168.0.3 public' do? I'd expect it would probably still need to have the '-c' though (I honestly haven't used snmp much).

See 'man snmpcmd' for details on the se flags.

['chris']

yes

# snmpwalk -v1 192.168.0.3 public

dosn't work, but

# snmpwalk -v1 -c public 192.168.0.3

works.

It seems, it needs to work both options:
-v1 and -c

greetings
chris

[Rick Garland]

True:

I do 'snmpwalk -v1 -c secret 1.1.1.1'

My belief is that this will also work;

snmpwalk -v2c -c secret 1.1.1.1

Using version 2 of snmp
The 'secret' is my community name.

Can also do 'snmpwalk -v2c -c secret 1.1.1.1 system

This will output only the OID info for system.

SNMPv2-MIB::sysDescr.0
SNMPv2-MIB::sysObjectID.0
SNMPv2-MIB::sysUpTime.0
SNMPv2-MIB::sysContact.0
SNMPv2-MIB::sysName.0
SNMPv2-MIB::sysLocation.0
SNMPv2-MIB::sysServices.0
SNMPv2-MIB::sysORLastChange.0

['chris']

hi Rick

# snmpwalk -v2c -c secret 1.1.1.1

is not working under Debian Sarge or freeBSD 5.4

greetings
chris

[Rick Garland]

The secret is the get-community-name. If you have not changed yours it would still be the default of 'public'

I have changed mine and by habit I use use the 'secret' in postings.

# snmpwalk -v2c -c public 1.1.1.1

Substitute the 1.1.1.1 IP address with a valid IP from your environment.

['chris']

ofcource I've changed and it doesn't work:

bsd# snmpwalk -v2c -c public 192.168.0.3
Timeout: No Response from 192.168.0.3

[Rick Garland]

You may not have version 2 of snmp

[J._1]

Chris,

Nobody has cleared up your original question though...

"knows someone why?"

Check the snmp package that you have installed. On your "older" versions, you're using the older ucd-snmp packages. On your new Debian system, you're using net-snmp.

You can use snmpconf to create your own "snmp.conf" file that specifies default values (i.e. output, version, and community string options). Place this file in your $HOME/.snmp directory. This makes things much simpler: your snmpwalk command could then be as simple as: "snmpwalk "

Do a "man 5 snmp_config" for more info.

Enjoy,
J

[Steven E. Protter]

Chris,

Side note: Beware that snmp, at least older versions does some of its authentication in a way that is shall we say less than secure.

You need to be current on patching and make sure you keep on eye on snmp exploits and such while using the product.

SEP
Rapid City, SD