Why does not my net-snmp listen to UDP6:161?

Question

1.00/5 (1 vote)

See more:

The version of my Net-Snmp in my embedded system is v5.9.3, kind of new. It works fine except not listening to UDP6:161. The command to launch SNMP daemon is:

snmpd -c <path>/snmpd.conf -x /usr/builtin/var/agentx/master

, where master is the UDP socket file.

The content of snmpd.conf at the above command is:

Quote:

rocommunity xxxx localhost
rocommunity public
rocommunity6 public
agentaddress udp:161,udp6:161

I googled and found that it's said it is enough to make Net-Snmp listens to UDP6:161 in such way. But when I used command 'netstat -uln', I found only 'udp :::161', without the expected 'udp6 :::161'.

I traced its excution by turing on the debugging and found the following 4 lines of message:

Quote:
115895:snmp_agent: installing master agent on port udp:161
115953:snmp_agent: init_master_agent; "udp:161" registered as an agent NSAP
115955:snmp_agent: installing master agent on port udp6:161
116011:snmp_agent: init_master_agent; "udp6:161" registered as an agent NSAP

From them, it's obvious that the udp6 port has been listening and registered. But why is there no 'udp6: 161' was shown at output of 'netstat uln'?

So, what did I missed? What should I still need to do to make it's work for UDP6?

What I have tried:

I explored this issue at the web by googling lots of discussions but in vain.

Posted 23-Mar-23 16:30pm

Stan Huang

Updated 29-Mar-23 16:53pm

v3

Add a Solution

Comments

Member 15627495 24-Mar-23 8:53am

:::161 is really IPv6 , it's the common mask for IPv6 addresses

read about feedback from 'netstat --uln'

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Stan Huang · Accepted Answer · 2023-03-29T16:53:00

Actually it works. The UDP6 port is being listened to. The 'netstat' command I used is from BusyBox and it shows UDP6 as

"

udp        0      0 :::161                  :::*

".

I looked for the first token of 'udp6' and thought the UDP6 port was not listened. It's my mistake while seeing the display of BusyBox's netstat.

So, the both UDP port 161 of IPv4 and IPv6 are being listened.