Hi, Does anyone know if you can route different domains through different gateways on Ubuntu? What I am looking to do is have multiple public IPs on one server so that the rDNS matches, which I guess isn't possible if they are all from 1 IP address? Thanks Dave
I guess you ask this because you want different rDNS records per domain. Why would you want to? Then you should also somehow need to change the server's hostname per domain, which is used in the helo/ehlo command and needs to be corresponding to the rDNS record. Also for TLS you'll need different per domain certificates. Again corresponding to the rDNS record. The only way I can think of to accomplish this is using different postfix instances.
Yes that is how I have achieved it, I have a frontend server which relays to other postfix servers, it works fine. But of course at a cost. I was thinking if I could route them on the same machine but via different gateways, I would only need 1 machine, a more powerful one. How does generic ISPs deal with 1 server handling so many domains and the rDNS not matching? For example GoDaddy.
RDNS must match the hostname of the server, not the domains for which the server handles emails. Large email providers clusters of mail servers. Each mail server has its own hostname, like mx1.provider.com, mx2.provider.com, and so on. Each domain that it handles, like client1.tld, client2.tld, does not need a rDNS record. The client domains just have multiple MX records, so that the provider can take down systems for maintenance at any time. behind that setup, you have a large central mail storage that all nodes have access to. E.g., I know an ISPConfig user who ran a 6-server ISPConfig email cluster at that time with about 15k email accounts and > 1000 domains. So different servers are not needed to run multiple domains and also not different IP addresses, a singe IP for each server is enough. Having multiple IP addresses or one IP for each client domain gives no benefits as long as you do not send mass emails or spam.
OK thanks, useful to know. Thanks for your recent advice, I have a 22 server ISPConfig setup running at the moment. I just want to build a new set which will be for a much lower amount volume of email, less than 300 a day but across different domains. I will just use 1 server in this instance. Thanks again!
300 emails a day can be handled by a single server 10 USD/month VPS, it can handle that even with moderate load per hour; why do you want to create a server setup consisting of multiple servers for that? The number of domains does not really matter, even if it were hundreds of domains.
No sorry the other setup is for 35,000 emails per day, multiple domain names etc. Its a recruiter emailing a big mailing list. The 300 one is a single server now I know about rDNS.
