I'm still trying to troubleshoot my problem getting Amanda to work though a 
firewall. I've read John Jackson's  port usage document and the FAQ at 
http://amanda.sourceforge.net/fom-serve/cache/139.html. I'd like someone to 
comment on whether or not I have the overall communication sequence correct 
below. Then, I'd like information on how this is different if amcheck rather 
than amdump is run.

In compiling amanda, I used these options: "--with-portrange=10080,10083 
--with-tcpportrange=10080,10083 --with-udpportrange=850,854".

This is what I understand concerning the sequence of port usage in making an 
amanda backup:

1. The tapehost makes a 'start backup' request of the client, originating on 
port 850-854 to port 10080-10083 using UDP. The contents of the packet contain 
a port number in the range 850-854 which is open on the tapehost, listening for 
TCP connections.

2. The client responds by sending a UDP packet from any (?) port to port 
850-854 on the tapehost. [Q: Can ports 850-854 on the tapehost be open to 
receive both UDP and TCP packets at the same time?] The contents of the packet 
are port numbers in the range 10080-10083 on the client which are listening for 
TCP packets from the tapehost.

3. The tapehost responds by sending a packet from port 10080-10083 using TCP to 
port 10080-10083 on the client. This packet starts the transmission of the 
backup data from the client to the tapehost, using the same port numbers just 
used.

Thanks for reviewing this and letting me know whether I've got it right. I 
appreciate your patience and help.

-Kevin Zembower


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E. Kevin Zembower
Internet Systems Group manager
Johns Hopkins University
Bloomberg School of Public Health
Center for Communications Programs
111 Market Place, Suite 310
Baltimore, MD  21202
410-659-6139