"Communication Closed by Client" in Messages file and "Crashed" Scan

[John Verry (OO)]

Running nessus 1.2 on Sun Netra X1 / Solaris 8 with 512 MB RAM.    Default Nessus settings except for dangerous plug-ins enabled, scanning ports 1-65,000, and dead-hosts appear in report.     If I scan a single host at a time – (the ones I’ve tried 3-4) have worked.   Kicked off scan of 30 hosts via GUI – results windows displaying process correctly.  Approx 14 of the hosts completed nmap and then plug-ins.  Approx 16 of the hosts stalled with nmap at 99% for extended period of time (approx. 1-2 hours).   On next check the GUI was shut down (although the nessus daemon was still up).  No output files (as far as I could tell – ideas appreciated).   I reviewed the nessusd.messages file and it looked normal to me (though I am far from experienced in troubleshooting nessus)   The last entries were –     Date Time Stamp [PID] Finished Testing X.X.X.X Date Time Stamp [PID2] Communication Closed by Client Date Time Stamp [PID2] Communication Closed by Client   Where PID2 was the PID spawned by successful logon.   I checked the nessusd.dump   /opt/lib/nessus/plugins/eftp_directory_traversal.nasl : Warning : evaluating unknown variable - soc /opt/lib/nessus/plugins/eftp_directory_traversal.nasl : Warning : evaluating unknown variable - soc /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/eftp_directory_traversal.nasl : Warning : evaluating unknown variable - soc /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/eftp_directory_traversal.nasl : Warning : evaluating unknown variable - soc /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/eftp_directory_traversal.nasl : Warning : evaluating unknown variable - soc /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! _socket_from_connection: bad fd <0> [7592] nessus_get_socket_from_connection: bad fd <0> [7592] nessus_get_socket_from_connection: bad fd <0> [7592] nessus_get_socket_from_connection: bad fd <0>   repeated n times (where ns is a lot)  The last 4 lines are   /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 ! /opt/lib/nessus/plugins/ftp_cwd_root.nasl - Requesting b[3] whereas b's length is 2 !     I’m not sure if the dump file is actually for the scan that closed.  The date is correct on the file but the reference to PID 7592 Is not matched in the .messages file (the only entry with that PID was from a different date).   Any suggestions as to how to troubleshoot this are appreciated.   John Verry