Sometimes you just need to tunnel UDP based protocols - such as SNMP - and the easiest ways is to use socat

$ socat tcp4-listen:6667,reuseaddr,fork UDP:DESTINATION:161
$ socat udp4-listen:161,reuseaddr,fork tcp:localhost:6667

And in combination with your normal SSH tunnel

$ ssh -L6667:localhost:6667 BASTION_HOST