Hello I have sent this email to the company that provide this snmp program, and they answered me as the following: I am running an snmp monitor to check devices in a network behind a firewall. SNMP traps seem to work ok (port 162). When, however, I try to poll an object (I have a VPN to the network by the way to access the internal addresses, but the devices must respond to the external address of the SNMP Monitor) I get response time out. When I check the network traffic I find that the responding device source is using UDP port 161 to send but seems to vary the destination UDP port (I am getting 3459, 1902, 2837, 2874, 1731, 1064, 1561, 1509, and some more) and I never find the querying device. How do I go about convincing a firewall to open all these ports for sending? Thanks in advance. Hanan The destination port will always be UDP port 161 when coming from the SNMPc. You should configure your firewall to allow packets that have UDP port 161 in either the source or destination port. As to how to do this, consulting the company that made the firewall would probably be your best source of information. Could you please explain to me what is that mean Is that mean that I need to allow port udp 161 for send and receive and that what I did also but still doesn?t work, or there is other solution that I didn?t understand from this email? Best regards hanan