"TCP Window Full" warnings in Windows Wireshark when Win11 ms-nfs41-client talks to FreeBSD NFSD

Aurélien Couderc <[email protected]> Fri, 26 Jun 2026 11:48:26 +0200
Newsgroups gmane.os.freebsd.devel.hackers
Message-ID <CA+1jF5oDekUqk6RH9u7f-xh2iVcQ8TSMEAQjGBNbaxjd+Hh1zQ@mail.gmail.com>
We get lots of "TCP Window Full" warnings in Wireshark running Windows
11 when ms-nfs41-client has mounted shares from a FreeBSD 16.0-CURRENT
NFSD.

The wireshark output looks like this:
69477 1330.696175200 192.168.132.130 192.168.202.239 TCP 14654 [TCP
Window Full] 600 → 2049 [ACK] Seq=41611537 Ack=18103445 Win=65279
Len=14600 [TCP PDU reassembled in 69488]

Windows has TCP Window scaling enabled, and uses 8MB send/recv TCP buffers.

How can I debug, or fix this issue?

Aurélien
-- 
Aurélien Couderc <[email protected]>
Big Data/Data mining expert, chess enthusiast