From: johngibson1541@yahoo.com
Date: Sat Feb 24 2007 - 14:46:07 ART
Reverse telnet is still a mystery to me.
It looks like such port number 2001 is only signifcant to IOS's telnet
client program, not any kernel module. The async device driver uses I/O
memory range. Right? And the TCP/IP stack on the kernel module side is
not aware of any process binding the 2001 port right ?
EXEC process is the equivalent shell in UNIX or windows model, right ?
IOS's telnet client program, when connecting to another device's console,
it assigns stdin and stdout file descriptors to the forked-from-shell
telnet client process, using context switching in UNIX model right ?
So, I think the port 2001 is still available to other processes. You can
assign port 2001 to finger and set up reverse telnet to port 2001 at the
same time.
When a different machine runs telnet to port 2001 to this mystery
machine, it will be served with finger.
When we do telnet to port 2001 on the local mystery machine, we will
be served with a forked-from-shell stdin and stdout.
What do we do if we want the finger service in the local machine? No way?
"telnet a.b.c.d 2001 use-tcp" ?
I am going to assume this. Going in to the lab in 2 days.
Another mystery is the rotary number in line mode.
Again, it is using tcp port. I have not thought about what the resource conflict issues are. What should I do? I should stop thinking about these.
John
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