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unable to snmp when ipsec tunnel on


background :

I'm using a debian server to monitor a RVS400. That server is on a public side and I decided to create an IPSec tunnel to secure those connection

debian <--- internet ---> modem <--- RVS4000 ---> internal network

Issue :

When bringing the tunnel up, the snmp is no more reachable

details :

tunnel down : i can snmpwalk my RVS4000 public IP from outside and from my internal network

tunnel up : i can snmpwalk neither my RVS public IP or private IP from my debian. I can snmpwalk the private IP from internal network though. I can ping both IP from my debian server

It looks like a bug or like i feature i don't understand

I'll stay around to provide any further details if you need.



Everyone's tags (3)

Re: unable to snmp when ipsec tunnel on

hi Alexis Moreau

Verifies that your IPSec tunnel not blocked ports 161 and 162, which are the ports of the SNMP protocol (Simple Network Manage Protocol), if these are blocked you can not manage your device

Also verifies that SNMP access is not blocked by a router access list that blocks the possibility to manage the router

To do this follow these instructions:

Go to Administration > Management

Router Access

Router Userlist: Select the desired router user list.

Router Username: Enter the user name here.

Router Password: Enter the password.

Re-enter to Confirm: Retype the password in this field.


SNMP Select Enable if you wish to use SNMP. To use SNMP, you need SNMP software on your PC.

System Name: Enter a suitable name to identify this device. It will be displayed by your SNMP software.

System Contact: Enter contact information for the system.

System Location: Enter the location of the system.

Read Community: Enter the SNMP community name for SNMP “Get” commands.

Write Community: Enter the SNMP community name for SNMP “Set” commands.

Trap Community Enter the SNMP: community name for SNMP “Trap” commands.

Trap To: Enter the IP Address of the SNMP Manager to which traps will be sent. If

desired, this may be left blank.


You can use Universal Plug and Play (UPnP) to set up public services on your network. When the UPnP function is enabled, Windows XP can add or delete entries to the underlined UPnP Forwarding Table. Some Internet games require enabling UPnP.

UPnP If you want to use UPnP, keep the default setting, Enable. Otherwise, select Disable.

By the way here I leave a user's manual for your device

If this answer was satisfactory for you, please mark the question as Answered.

Greetings, Johnnatan Rodriguez Miranda.