local net connectivity---help

[Gerald I. Evenden]

I am using a Linksys Wireless-G router to connect my:

1. desktop Kubuntu via ethernet
2. Dell Ubuntu Feisty laptop via wireless
3. wife's laptop XT via wireless
4. Apple G4 laptop (to be given away shortly) via wireless

The Linksys is connected to a Zoom router/modem to DSL.

Everything works fine when talking to the outside word but I am
frustrated trying to interconnect the [k]ubuntu systems via SSH
and similar procedures.

The [k]ubuntu reject all forms of access from an outside source.
The Apple is the only machine that will allow access via SSH: that is
I can ssh my user on the Apple via ssh xxx at ip-number but none of
the ubuntu machine will not allow access from neither the Apple nor
an ubuntu.

Part of my problem is finding manuals on how to set something
like this up for the [k]ubuntu systems.

It would also be nice to be able to refer to the system by
me at charon rather than me at 123.123.123.123 .

Suggestions and/or reading list would be most appreciated.
-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939)  British psychologist