It is possible to create network address sets of trusted hosts which you can allow other hosts to accept connections from.
If you have static IP address it's relatively simple.
For example, you could create a Network Access Control rule that allows all hosts to accept connections from x.x.x.x on TCP port 161 if you had something using SNMP.
You'll just need to determine what IPs and ports to allow if that's all that's preventing it.
