0

I have two types of software connected to the internet - both HAVE to be continuously connected. One connects via UDP protocol and I have no dropouts. The other maintains its connection through a TCP protocol and I have frequent dropouts with the message "no network activity for 4 minutes."
The software provider tells me is it my ISP.... My ISP tells me is must be the modem.... the modem people are yet to respond.

Can someone shed some light on this issue for me PLEASE. Thanks you Sol

Improve this question
4
  • 3
    Are you sure the UDP device is continuously connected? UDP is a "fire and forget" protocol, while TCP needs acknowledgements. Have you dumped the packets being sent and received in each side if the connection to narrow the problem space? What OS's are involved and have you checked your firewalls? Commented Sep 12, 2019 at 20:02
  • yes UDP always connected. Commented Sep 12, 2019 at 20:06
  • Windows 10 on my side - don't know about server side... and what would I check in firewalls?? thank you Commented Sep 12, 2019 at 20:07
  • For the firewall you would check that UDP packets are allowed outbound and inbound (or established, related) - but I'm not a Windows person. You should also check on your router. On your router you need to check that NAT/connection tracking/port forwarding allows traversal of packets. You really need to specify the protocol/software . Another thing to check is maybe keepalives - maybe your router is forgetting about the UDP "connection" because the connection tracking is timing out. Commented Sep 12, 2019 at 21:22

1 Answer 1

Reset to default
1

UDP protocol is connection-less.

Firewalls are usually state-full. They have some internal tables for connection tracking. Those tables have entries that are created for each network flow. The entries in those tables have timeouts. The timers for those entries are reset each time a new packet from the flow is seen. If a flow is idle for too long time it gets removed from connection tracking table and new packets are discarded or rejected.

You need to know the network topology and make captures on the path to isolate the issue. Then dig deeper into the config of the equipment that is dropping/rejecting the packets.

Improve this answer
3
  • thank you - your comments take me to the next step .... just wish it was easy to solve. Commented Sep 12, 2019 at 21:01
  • 1
    Update your case with more details and we can help you further. Commented Sep 12, 2019 at 21:15
  • most probably you have asymmetrical routing happening, so packets are flowing back via a different route or a different firewall interface. Check the next hop at each point in the traffic flow. Commented Sep 12, 2019 at 23:29

You must log in to answer this question.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.