I'm not sure how to setup the following config:
Linux should connect to ISP, fixed IP. ISP (demon) knows the machine as <something>.demon.nl
I also want run a local domain (like home.net), with a couple of other machines. Those machines should use the Linux pc as a gateway to internet (masqerading), and query the DNS on the linux PC only. They will be configured using DHCP. I have gotten Linux to dial-up the ISP, have got the DNS to work so that all requests are handled were I want them, but...
currently the hostname is <something> and the domain is demon.nl. I'd really like to change that to <myLinux>.home.net, and add home.net to the local DNS. I would assume that <something>.demon.nl must still be used for the ISDN connection to ISP, and use the local names for eth0 and other IP's (192.168.7) I want to use.
Will this work, without causing trouble for ISP? Also, is there something in the DNS I should look into, currently the DNS handles 127.0.0.0, and forwards everything else through ISP DNS (using forwarding).
Next step would be to get the Linux PC to act as mail relay, but I receive e-mail using SMTP, so I must be known as <something>.demon.nl when connecting to ISP. All mail sent to <somebody>@<something>.demon.nl is delivered to me, so I want to be able to decide on a per <somebody> basis if the mail should go local on the Linux PC, held until another machine in my domain connects and uses SMTP to retrieve any mail waiting for it, or rejected (bounced). All local (to my machine) mail should be processed straight away. Mail intended for a machine in my doamin should be held until it connects. All mail that should go outside, should be sent to mailer of ISP, once or twice a day. Mail shouldn't build the connection itself, which might be a problem. Current config is setup so that any reference to an IP outside of 192.168.7.xxx or 127.0.0.1 will start a connection to ISP, which is dropped after 30secs.
Not looking for a cook book answer, just the most relevant points. I can config the DNS, modify route tables and the like. I know nothing about sendmail, but have quite a lot of docs, it is knowing where to look for the right options, and how to combine that is causing the probs.