Remote Connections and Source Ports Changing

[lordjay]

Hi,

I have spun up Cacti on DigitalOcean and everything is working locally.

Currently, I am trying to add a switch on another network but run into the error System SNMP error - SNMP::get(): No response from [wan ip]

From doing a tcpdump, I have been able to verify that the port forward is working except for that the source port is random and not 161 which is port I have setup for this connection.

What I am trying to figure out is why the source port is changing? Is that a cacti thing? ISP? Digital Ocean? and if there is a work around or a better way to setup a remote connection to the cacti server?

Thanks for any help and input.

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[TheWitness]

Once you can perform an SNMP walk or get from the command line, it should also work from the GUI. Let that be your challenge. Firewalls make it difficult.

[lordjay]

Understood. I'll focus on those commands.

For the source port that is randomly changing on each request, where would you recommend I start? I start spinning out on the logic.

Is the firewall/router on the network I am trying to connect to changing it?
or
Is Digital Ocean's VPC changing the port before going out into the world?

Thanks for the help.

[TheWitness]

Source ports don't matter, and it's intentional.

[lordjay]

Still stumped. I have tried SNMPWALK to other remote machines and running into the same issue. I am able to verify that the port forwarding is working so I am starting to wonder if it is my snmpd.conf file.

Does anything look off or am I missing something?

Code: Select all

###########################################################################

#agentaddress  127.0.0.1,udp6:[::1]
agentAddress udp:161,udp6:[::1]:161
agentAddress udp:162,udp6:[::1]:162


###########################################################################
# SECTION: Access Control Setup
#
#   This section defines who is allowed to talk to your running
#   snmp agent.

# Views 
#   arguments viewname included [oid]

#  system + hrSystem groups only
view   systemonly  included   .1.3.6.1.2.1.1
view   systemonly  included   .1.3.6.1.2.1.25.1


# rocommunity: a SNMPv1/SNMPv2c read-only access community name
#   arguments:  community [default|hostname|network/bits] [oid | -V view]

# Read-only access to everyone to the systemonly view
# rocommunity  public default -V systemonly
# rocommunity6 public default -V systemonly

rocommunity CHTCacti localhost
rocommunity CHTCacti xxx.xxx.xxx.xxx
rocommunity CHTCacti xxx.xxx.xxx.xxx
rocommunity CHTCacti xxx.xxx.xxx.xxx
 

Thanks for any help.

[TheWitness]

Looks like the loopback interface. Here is what I use.

Code: Select all

rocommunity public
rocommunity6 public
agentaddress udp:161,udp6:161
sysContact Dads Place (North)

That's it, nothing else.

[lordjay]

Wanted to update the thread and say I got it working!

After all said and done, the issue was the switch of all things. Basically, the SNMP server allowed me to add an IP address and I kept adding the cacti server and for some reason it failed but once I took out the address and just used the community name. Voila!

Attached is the photo of the interface. This was a Pakedge MS2424.

Thanks for support and guidance.