Network bug on ESET internet security (Win10)

[Mateusz Belzak 0]

Hello,

I could not find other way to report bug I found with default configuration on ESET Internet Security (Windows 10),

straight after activation ESET breaks PMTUD, any packets with don't fragment flag set are being randomly modified and flag cleared so it allows IP fragmentation as a result. I have also noticed that traceroute is broken always pinging destination on first hop (this is due to TTL field being reset to default 128). I don't think it's correct behaviour unless I don't understand something.

Once switched from Internet Security to NOD32 I don't have this problem and PMTUD & traceroute behave as they should.

I can provide more information if needed.

My product version is 17.1.9.0
OS: Win10 64bit

[Marcos 5,450]

Does disabling HTTP/3 network traffic scanning in the advanced setup make a difference?

[Mateusz Belzak 0]

Thank you so much for your quick response Marcos.

Disabling HTTP/3 network traffic scanning fixes my problem. No biggie as I block UDP 443/80 by default.

[Marcos 5,450]

Please kindly proceed as follows:
1, Enable advanced network traffic scanner logging (advanced setup -> Tools -> Diagnostics)
2, Start capturing the network communication with Wireshark
3, Reproduce the issue
4, Stop logging and save the Wireshark log.
5, Collect logs with ESET Log Collector
6, Supply us with both ELC and Wireshark logs for perusal.

[Mateusz Belzak 0]

Hi Marcos,

Sorry for my late reply.

Not sure if there was an update but now it all works fine with HTTPS/3 scanning enabled.

Thanks

Mateusz