SNMP traffic not detected in firewall

RouterOS General
1

I struggle getting SNMP to work on my WAN interface (that is from the Internet and towards my Mikrotik Routerboard that acts as both a router and firewall on my home network. If I run

/ip firewall filter print

, I get the following output (non-relevant rules are removed):

 0   chain=input action=accept protocol=udp dst-port=161-162

Also, to ensure that SNMP is activated, I run this command

/snmp community print

that returns:

Flags: * - default 
 #   NAME     ADDRESSES                                          SECURITY   READ-ACCESS
 0 * public   0.0.0.0/0                                          none       yes

When I try to test the connection, by running

snmpwalk -v1 -c public <public ip address to home network>

there is no response - but even stranger, the firewall (if I look at the rules in WinBox) indicates that NO packets are detected on the rule I created!

I suspect that my ISP could be blocking UDP/161 from the internet and towards my home network, but to my knowledge I cannot verify this unless I disconnect the Mikrotik router and connect the WAN port to my computer to remove the ISP from the equation. Is there another way I can troubleshoot this?

2

Yes, there is another to troubleshoot it. Create a VPN to the router and re-test. That will take the ISP out of the equation.

3

Hi, thanks for the reply.

That was a good idea, but I did not have to go for that option. I sent an email to my ISP and asked if UDP/161 was blocked, and they replied that it was because they had detected a security issue with the standard router they sent out to their customers. Once I explained to them that I did not use the standard router, but a Routerboard, they opened the port.