SNMP - Port DSNAT - not working -

Hello guys and ladies,

hope you are doing well and i would like to ask you for support regarding SNMP DSNAT on my Mikrotik.

Here we go lets explain the situation:

I want to check my RB via SNMP. It seems that ISP blocks port 161 so i choose port 8230 as a port from the internet. I created DSNAT from port 8230 to internal address of Mikrotik 192.168.10.1 to port 161.
In Firewall > NAT i can see that bytes are counting in the rules. But only 1byte per minutes lets say.

What is the problem: Not able to connect to SNMP connection. At home with the prety same configuration its working.

SNMP on Mikrotik is enabled and reachable via Local network. So i suspect NATing as a problem.

How can i debug it please?

Please check my configuration if possible:

/ip address
add address=192.168.15.1/16 comment="default configuration" interface=bridge2 \
    network=192.168.0.0
add address=85.205.100.248/28 interface=ether1-gateway network=85.205.100.240
add address=172.100.0.2/30 interface=gre-tunnel1 network=172.100.0.0

/ip firewall filter
add action=accept chain=input comment="default configuration" protocol=icmp
add action=accept chain=input connection-nat-state=dstnat dst-port=161 \
    log-prefix=SNMP protocol=udp src-address=37.31.68.246
add action=accept chain=input dst-port=1723 protocol=tcp
add action=accept chain=input dst-port=500 protocol=udp
add action=accept chain=input dst-port=1701 protocol=udp
add action=accept chain=input dst-port=4500 protocol=udp
add action=accept chain=input comment="default configuration" connection-state=\
    established
add action=accept chain=input comment="default configuration" connection-state=\
    related
add action=drop chain=input comment="default configuration" in-interface=\
    ether1-gateway
add action=accept chain=forward comment="default configuration" \
    connection-state=related
add action=drop chain=forward comment="default configuration" connection-state=\
    invalid
add action=accept chain=forward comment="default configuration" \
    connection-state=established
add action=accept chain=input disabled=yes
/ip firewall nat
add action=masquerade chain=srcnat comment="default configuration" \
    out-interface=ether1-gateway to-addresses=0.0.0.0
add action=dst-nat chain=dstnat disabled=yes dst-address=85.205.100.248 \
    dst-port=80 protocol=tcp to-addresses=192.168.10.110 to-ports=80
add action=dst-nat chain=dstnat dst-address=85.205.100.248 dst-port=8230 \
    protocol=udp to-addresses=192.168.15.1 to-ports=161

Cancella gli IP veri dal post precedente…
o se li hai messi finti, non scrivere indirizzi di altri…

Yea. These IPs are fake.

Thank you for any answer.

Dominik

Please be polite when using a fake address…
don’t use a real address …
With IPv4 gone, you pretty much always guess…

Use instead unused / unassigned from 225.x.x.x to 231.x.x.x

SNMP use port 161 and 162, but if you change src port number, not all device are compatible, because expecting connection only from that ports.

Aha.

Does it mean that i should also do DSNAT 162 port?

Or any another advice what to try?

Thanks a lot!

The solution can be one VPN…?
I can’t suggest you further, because is too hard on forum…

Is there any way how to confirm that the device is not compatible? I would like to debug it.

BTW in connections i can see there is a connection established ( somehow )