Download Failure

[spetrillo]

Hello all,

I have a Plesk server behind my OPNsense firewall. Everything has been working but recently I cannot seem to download an updated installer file, as Plesk says the following:

Getting new version of Plesk Installer...
Downloading file parallels_installer_Ubuntu_22.04_x86_64.md5sum: 100% was finished.
Downloading file parallels_installer_Ubuntu_22.04_x86_64 (retry 3 of 3): Operation too slow. Less than 500 bytes/sec transferred the last 30 seconds           
ERROR: The required version '3.77.1' was not found on the server.
This could happen because of configuration error at the installation source.
Failed to download the file http://autoinstall.plesk.com/Installer/3.77.1/parallels_installer_Ubuntu_22.04_x86_64 (84.17.59.10):
Operation too slow. Less than 500 bytes/sec transferred the last 30 seconds
Not all packages were installed.
Please try to install packages again later.
Please resolve this issue and try to install the packages again.
Visit https://support.plesk.com/ to search for a solution.
exit status 1

I spoke with Plesk support and they indicated:

It may be due to some firewall restriction or outbound traffic is filtered. I suppose it is related to network/MTU. Large file uses full TCP window and due to that fragmentation needed. NAT/router drops fragmented packets and due to that connection stalls. As the issue is server wide, please contact your server/network provider to check the network/NAT gateway settings to allows to download bigger files.

Where 8n OPNsense would I look for anything related to NAT settings? I have been running Plesk behind OPNsense for almost 2 years and not sure what changed.

Thanks,
Steve