Logical Ip address and route for VPN

[Steve Post]

The numbers of the IP addresses have been changed to protect the innocent.

I have one computer (call it computer A) with one lan card with 1 ip address and 3 more logical ip addresses.

lan1 1.1.1.20
lan1:1 1.1.1.21
lan1:2 1.1.1.22
lan1:3 1.1.1.23

Network guys set up a VPN to allow me on 1.1.1.22 (and only 1.1.1.22) to ftp to 2.2.2.117 (let's call it computer B).

From computer A, I type "ftp 2.2.2.117".
It fails.
When I run ftp, am I travelling from computer A to computer B. But am I trying to connect from 1.1.1.20, or 21, or 22, or 23?
Is there a way to tell the computerA that I want to connect to 2.2.2.117 ONLY through local ip address 1.1.1.22?

Can this be done through the route command? My netmask on computer A is 255.255.255.0.

This is HP9000, running hpux11.0.

[Jeff Schussele · Accepted solution]

Hi Steve,

It depends on how the ARP tables are kept on the remote system & network devices enroute.
I think that if the tables will only hold one entry per MAC address, then the "primary" IP will be the default entry.

I'd set up enhanced logging (inetd -l) on the remote system & see which IP it reports as connecting an ftp session.

There's no way to "force" the IP with route commands - it's the entry that the ARP table gives it that will be used.

Rgds,
Jeff