2025-06-02 20:15 AEST by Arthur Barrett - Just noting this error from CVSNT 2.8.01.6610 to a more modern server

THIS IS NOT AN ERROR - IT MEANS THE SERVER OR CLIENT NEEDS UPDATING

But maybe the error message could better explain the problem and a soltution?  Or the eBook could?


cvs ver
FATAL ERROR: Couldn't agree a client-to-server cipher (available: chacha20-
poly1305@openssh.com,aes128128-gcm@openssh.com,aes256-gcm@openssh.com)
cvs [version aborted]: Error writing to server WSA_INVALID_EVENT




cvs -v

Concurrent Versions System (CVSNT) 2.8.01 (Soolin) Build 6610 (client/server)

Except where noted this program is Copyright (c) 2006 March Hare Software Ltd.

2025-07-06 10:35 AEST by Arthur Barrett - See bug 7366 - "FATAL ERROR: Couldn't agree a client-to-server cipher"

So the workaround is: add aes256-ctr to  /etc/ssh/sshd_config

The 'fix' is for us to upgrade the inbuilt SSH client to support aes256-ctr

making this dependant on upgrading putty bug 7190 and on bug 7366

Newer releases (on or after 7272) of CVSNT have an upgraded putty so this should be fixed.


This problem specifically shows up on OLDER cvsnt clients, eg: here it was CVSNT 2.8.01.6610

So we can't "fix it", we can't even improve the error message (in old releases).

I guess one day the same thing will happen with the current release, so we can improve the message NOW 
for when this problem occurs in the future.  Or as has been described above, we could include some 
documentation in the eBook about SSH ciphers.  The notes in bug 7366 are a good starting point.