CODEWITHSUNDEEP
socketstcpclientfirewall
Harsh
Harsh

Reputation: 3751

TCP communication stops with firewall on

I am having a server client application developed in vb.net. The server app sends a file to the client app at regular intervals. It uses TCP/IP to send files.

After installing the application the application runs fine with firewall off. But when firewall is on and an exception is added for the application, the file transfer works for around 10 mins and then stops.

But as soon as i turn off the firewall, the transfer starts again. Please suggest how to resolve this issue.

Upvotes: 0

Views: 458

Answers (1)

munkeyoto
munkeyoto

Reputation: 309

When you say "file transfer works for around 10 mins and then stops" can you elaborate a little more. For example... "I am transferring a large file and during the transfer, it stops." or "I transferred a file successfully, and ten minutes later, went to transfer another, and it didn't work."

In the first scenario (large transfer), there may be some form of bandwidth limitation/rule stopping. In the second, there could be some form of "STATE" processing where a STATEFUL session occurs, the firewall doesn't close it, another initiation is made 10 minutes later, and your firewall is viewing the session "someone is trying to piggyback/hijack this session... better close it"

I would turn on verbose logging on the firewall to see what the firewall is doing and how it perceives the connection.

Upvotes: 1

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