We have an in-house application for sending large files. Using TCP/IP this application uploads the files to a server on our main office network and then sends a link to the file as part of an email. For the past few months this service has had intermittent timeout issues when the file is being uploaded to the server from a branch office. When we do a packet capture we see lots of dropped packets occurring on the encryption/decryption subsystem with the following error:
Drop Code: 138(IDP detection OOO Exceeded Max), Module Id: 25(network)...
The error is seen from the main office firewall on packets sent from a branch office. Users from our home office where the server sits have no issues. Users outside of our network sending files into our network have no issues. It's only branch users who are having issues. We are using site-to-site VPN to connect the branch offices to the home office.
I've been following a similar issue on SpiceWorks and tried the solutions mentioned there but nothing is working. We are on the latest version 220.127.116.11. Any suggestions?
Note - I am a software developer and not a network admin