2960x switch VLAN port to WAN IP, configuration

[Jorge Bixiga]

Hello

Often times, IT managers at our installations are not able to properly configure the following, to allow for unrestricted traffic between end points.

Scenario:

Alarm system IP address scheme (ip 10.0.0.221, subnet 255.255.255.0, gateway 10.0.0.1) connected to VLAN port 24 in cisco 2940x switch at customer's network.

Alarm system sends secure packets to WAN IP (receiver's WAN IP address).

Receiver acknowledges the secure packet, checks off the signature from the sender, and returns it to sender.

Sender receives returning secure packet from receiver, with original signature check mark.

Packet has successfully made the secure round trip traffic.  This goes on 24/7 365, every few seconds.

Thing is: IT managers are not able to configure switch properly, failing at allowing for packets to return to sender.

I don't know enough to tell them where to look, in the configuration of the switch.

Any help is appreciated.  Thanks.

[Philip D'Ath]

The switch will either forward packets - or not.  Is your issue happening all the time (aka completely broken), or working all the time?

If the issue is intermittent then it is not so likely to be a switch.

[Jorge Bixiga]

completely broken, not working at all.  they can see in the monitoring where the alarm panel is sending the packets to (to a remote receiver's WAN IP address), but packets are obviously not making their way back to the alarm panel.

 If not at the switch level, then the problem may be at the router level, also Cisco routers (some customers that have this problem use Sonic Wall, Watchguard, Checkpoint, and Cisco ASA routers).

When the customer's network is less sophisticated (ie Verizon FIOS modem, or TWC modem connected to dummy 10/100 switches), then there are no problems.

[Philip D'Ath]

I'm going to guess this is probably more of a firewall issue that a switching issue.