I'm using amanda-2.4.4p2 but I have also tried 2.4.5b1-20040510 with the same 
results.

I have trouble upgrading from 2.6.5 to 2.6.6, I have narrowed it down by trying 
the different rc releases. Between 2.6.6-rc1 and
2.6.6-rc2 something happens that make my amanda backups fail with the error 
[bad CONNECT response].

If I do nothing else than boot to 2.6.6-rc1 from rc2 it works so it seems to be 
somthing with the kernel that is causing the
trouble, but I don't know how to investigate further.

This is the best debug info I've found so far.

Non-working:
root@zappa:/var/tmp/amanda# cat sendbackup.20040511223325.debug
sendbackup: debug 1 pid 2463 ruid 0 euid 0: start at Tue May 11 22:33:25 2004
/usr/lib/amanda/sendbackup: version 2.4.4p2
  parsed request as: program `GNUTAR'
                     disk `/boot'
                     device `/boot'
                     level 1
                     since 2004:5:11:10:6:42
                     options 
`|;bsd-auth;index;exclude-list=.amanda.excludes;exclude-optional;'
sendbackup: try_socksize: send buffer size is 65536
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.564
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.565
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.566
sendbackup: time 0.008: waiting for connect on 564, then 565, then 566
sendbackup: time 30.003: stream_accept: timeout after 30 seconds
sendbackup: time 30.003: timeout on data port 564
sendbackup: time 59.998: stream_accept: timeout after 30 seconds
sendbackup: time 59.998: timeout on mesg port 565
sendbackup: time 89.994: stream_accept: timeout after 30 seconds
sendbackup: time 89.994: timeout on index port 566
sendbackup: time 89.994: pid 2463 finish time Tue May 11 22:34:55 2004

Working:
root@zappa:/var/tmp/amanda# cat /tmp/amanda/sendbackup.20040611030533.debug
sendbackup: debug 1 pid 26091 ruid 0 euid 0: start at Fri Jun 11 03:05:33 2004
/usr/lib/amanda/sendbackup: version 2.4.4p2
  parsed request as: program `GNUTAR'
                     disk `/boot'
                     device `/boot'
                     level 0
                     since 1970:1:1:0:0:0
                     options 
`|;bsd-auth;index;exclude-list=.amanda.excludes;exclude-optional;'
sendbackup: try_socksize: send buffer size is 65536
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.840
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.841
sendbackup: time 0.003: stream_server: waiting for connection: 0.0.0.0.842
sendbackup: time 0.020: waiting for connect on 840, then 841, then 842
sendbackup: time 0.020: stream_accept: connection from 192.168.20.100.36640
sendbackup: time 0.021: stream_accept: connection from 192.168.20.100.36641
sendbackup: time 0.021: stream_accept: connection from 192.168.20.100.36642
sendbackup: time 0.021: got all connections
sendbackup-gnutar: time 0.023: doing level 0 dump as listed-incremental to 
/var/lib/amanda/gnutar-lists/zappa.zappa.cx_boot_0.new
sendbackup-gnutar: time 1.495: doing level 0 dump from date: 1970-01-01  
0:00:00 GMT
sendbackup: Can't open exclude file '/boot/.amanda.excludes': No such file or 
directory
sendbackup: time 1.568: spawning /usr/lib/amanda/runtar in pipeline
sendbackup: argument list: gtar --create --file - --directory /boot 
--one-file-system --listed-incremental
/var/lib/amanda/gnutar-lists/zappa.zappa.cx_boot_0.new --sparse 
--ignore-failed-read --totals --exclude-from
/tmp/amanda/sendbackup._boot.20040611030535.exclude .
sendbackup-gnutar: time 1.589: /usr/lib/amanda/runtar: pid 26361
sendbackup: time 1.589: started index creator: "/bin/tar -tf - 2>/dev/null | sed -e 
's/^\.//'"
sendbackup: time 2.754:  53:    size(|): Total bytes written: 10414080 (9.9MB, 
8.5MB/s)
sendbackup: time 2.758: index created successfully
sendbackup: time 4.266: pid 26091 finish time Fri Jun 11 03:05:38 2004

Thanks for any help.

Let me know if I need to post more info, don't want to write an unnecessary 
overly large e-mail.
/Andreas Sundstrom