Interop problem with old dropbear and new openssh

Graham Cobb g+dropbear at
Sat Oct 1 05:38:14 WST 2011


I have a router running an old version of OpenWRT with an old version of 
dropbear (Dropbear sshd v0.44test3).  It has been working for many years and I 
ssh in from my desktop systems (running Debian Testing) with no problem.

However, recently I upgraded one of my desktops and I can no longer connect to 
the router.  Dropbear on the router is exiting with:

exit before auth: bad buf_getwriteptr

The desktop is running "SSH-2.0-OpenSSH_5.9p1 Debian-1" (it failed with 5.8 as 
well).  However, another desktop still running "SSH-2.0-OpenSSH_5.5p1 
Debian-6" still works fine.  The config files are identical.

I realise this is a very old version of dropbear and that you are not 
responsible for changes in OpenSSH but I thought I would ask here in case 
anyone else has seen this and can maybe suggest a config change to workround 
the problem!


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