ChangeIP.com Forums

Hi folks,

just joined this forum.

I finished installing an Ubuntu-6.06.1-LAMP-server-amd64 for test purpose to absorb knowhow on server building. I'm running ADSL broadband with dynamic IP which changes on connection.

I'm searching for a free domain to complete my test and come this site.

Please advise is the free domain offered by changeip.com will be suitable for my application. TIA

B.R.
satimis

Sure - you can use our free subdomains just like any other domain.

Hi master,

Thanks for your advice. The test has been finished sometimes ago.

I'm now testing server consolidation on Virtural Machine running kernel virtualization. It is possible running >100 servers as daemon on the same Virtual Machine sharing resource. Coming to networking I haven't figured out how to share ONE external connection (one fixed IP) amongst all servers doing the same job (for simplicity, say running all of them as mail server). Working on a range of fixed IP there will be no problem. Running all of them as Apache server it may work similar to virtual hosting. Mail server needs port 25. I'm prepaired to work on namebase, i.e. all domains pointing to the same IP and run an internal DNS server to distribute the incoming mails to the respective mail server based on domains. Proxy may help. I'm still searching heavily on Internet to collect technical information. Any hint/suggestion? TIA

B.R.
satimis

In this case you will need some type of proxy / middleware that would direct the smtp connection to the right machine. This is very tricky because there are no host headers like http has. By the time you have connected to port 25 and sent the EHLO, MAIL FROM, and RCPT TO you are already connected and it's too late to hand off the connection.

You can use our smarthost / store and forward service to allow us to deliver mail to your hostname:64000, hostname:64001, hostname:64002, etc. You can then use a port other than 25 for each virtual machine.

Sounds like you need to make a single incoming virtual smtp server, and then it just redirects the mail to each individual smtp host on the inside.

Hi master,


Thanks for your advice. This is only a test.

The Host is a headless base server without application running other than a text editor. It can be seen by outside world. It is used to configure the Guests. In case I need GUI on configuration I'll use a workstation to do the job remotely.

The Guests are also headless server running web/mail server as daemon. To build a new mail server is rather simple only cloning a source mail sever, changing the local IP and hostname.



Could you please explain in more detail. What port shall I forward to the Guest on the router? If there are >100 mail servers running on the box then I need >100 different ports to do the job.



I'm exploring a possible simple and reliable solution. I can use a base Guest server to build device. I can build a powerful router on the box, vyatta.org.

Could you please explain more of your suggestion? TIA


B.R.
satimis

Yes, that last option where you build a guest that does only smtp redirection would be the best option. You can then forward mail using private IPs on the inside, ie 192.168.222.100 - .199 for example. The smtp gateway would have static routes for each domain to know which internal IP to forward the mail to.

Check out www.Mikrotik.com - they have the best linux firewall / router around : )

The network setup on the Host has an external IP (the fixed/static IP). Each Guest has it own local IP (fixed), e.g. 192.168.0.100 - .199. If all domains point to the same static IP how can the router distribute them to the respective mail server.



Thanks. I'm running Iptables which together with the rules on Postfix, host deny and host allow forms a very rigid firewall. I'm considering whether the rules on package filtering/forwarding can assist me.


B.R.
satimis

What I meant was for you to setup another guest that does smtp for the public side. So the router forwards port 25 for everyone to smtp server 1. smtp server 1 then determines which internal IP the mail should go to and forwards it, ie to smtp server 2.

internet -> router -> port 25 -> smtp server 1 using internal IP (guest) -> decides to send to smtp server 2, 3, or 4, etc based on domain.