> Point taken. I suppose the reason the static IP configuration doesn't
> work with the other network is the differing default gateway address?
Mre than that, it's a whole different network addressing scheme
(possibly).
Don't know what you know about IP addressing but here's the short
version:-
Two machines on the same network, say A and B with addresses 192.168.0.2
and 192.168.0.3 each with a mask of 255.255.255.0
If A wants to talk to B, then it needs to know whether to send it direct
or route it. It determines the answer to this question by performing a
logical AND of its address with its mask so ends up with 192.168.0.0, it
does the same with B's address and gets 192.168.0.0.
Hey, that's the same so it knows that it can send on the local network.
If it wanted to talk to a machine 194.65.32.3 then the result would be
194.65.32.0
192.168.0.0 is not the same as 194.65.32.0 (no shit Sherlock!) and so it
knows that this third machine isn't on the same network. Machine A then
looks in it's routing table to see if it has a known route to this new
network and if it doesn't then it simply sends it to its default gateway
(if configured) and lets the gateway forward the packet on.
So, the static IP configuration isn't going to work if either the
network addressing scheme results in a foreign network or the default
gateway is wrong.
For example, if you're home network was 192.168.0.0 and your work
network was 192.168.0.0 and your friends network was 192.168.0.0 and you
all had a default gateway of 192.168.0.1 then from an IP perspective you
could configure statically and work at all locations. However you might
have trouble sending email if your email provider refuses to accept the
connection from external or doesn't use authenticated SMTP.
On the other hand if your home and work were on 192.168.0.0, at home you
had a gateway address of 192.168.0.1 but at work they had 192.168.0.128
then you would be able to communicate with every local machine but
wouldn't be able to route externally because your setting for the
gateway was wrong.
This is why DHCP exits, set it up and it just works.
There are reasons why static addressing has a place but ease of
configuration and security aren't two reasons. The only exception to
this with regard to security is where you might be filtering traffic
to/from other machines based upon IP address for example port forwarding
to an internal host or in a corporate firewall to track internet usage.
Tracking internet usage this way isn't particularly useful though as it
in itself does not provide for non-repudiation and it's far better to
track usage by authenticated username.
David.