Re: bin/59865: ftp should not set socket send/receive buffers unless told to

[gnats-admin%netbsd.org@localhost]

The following reply was made to PR bin/59865; it has been noted by GNATS.

From: mlelstv%serpens.de@localhost (Michael van Elst)
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: bin/59865: ftp should not set socket send/receive buffers unless told to
Date: Fri, 26 Dec 2025 23:32:57 -0000 (UTC)

 cmeerw%cmeerw.org@localhost writes:
 
 >Even if no socket buffer sizes are specified, ftp still gets and sets the socket buffer sizes. This has the side-effect that it disables auto-sizing of the socket buffers, resulting in slow file transfers (particularly over high-latency connections).
 
 That is mixing up two things, as you say because of a (historical)
 "side-effect".
 
 The better way is to remove that side-effect, which is currently
 possible by setting kern.sofixedbuf=0 with sysctl. Then configuring
 a buffer size just overrides the initial size (net.inet.*.sendspace,
 net.inet.*.recvspace) and keeps auto-sizing enabled.
 
 N.B. configuring a socket buffer size and using the same value for
 the size of I/O operations, as done by ftp, isn't optimal either. But
 that's a different issue.