Email always gives me a headache. My company owns a webserver which we are using to host our clients e-mails and websites. Currently we have about 30 clients being hosted off the same server, with only 3 using hosted e-mail. Recently we got blacklisted and this has caused some problems. Can anyone advise me of the best way to host multiple email domains off of just 1 server, would I need a static ip address per email domain with it's own reverse dns? Does the reverse dns need to match the email server domain? (e.g. Email server reply to helo with mail.domain.com, mx = mail.domain.com and reverse dns = mail.domain.com) Can the server be set up as a smart host? and if so how do I configure the reverse dns for this? I have also just realised that we cannot email AOL - any message sent from the server/website/email account does not make it through, however replying to an AOL initiated email will be delivered. Any ideas anyone? Thanks in advance
Have you found out the reason you were blacklisted? It's essential to know it to recommend you anything.
I've justed checked with mxtoolbox.com and the reason given is "WARNING: No Reverse-DNS (PTR) is assigned to your IP Please request your Admin or Provider to fix this." - However the ip has a reverse dns, but it doesn't resolve to mail.domain.com (where emails are coming from) - I have more than 1 emails domains running from this ip and the reverse ptr record points to another mail server (mail.otherdomain.com).
For AOL: You need to fill out a whitelist request form. You may already be on their spam list, and you will need to request a removal first. They require your IP's to have reverse DNS (Doesn't need to be to the exact domain), and the domains need to have proper SPF records. http://postmaster.aol.com/
Steve, When mail is sent from your server it is sent as the servername. You could be hosting 1000 domains, its irrevelant. What matters is the hostname defined to your smtp server, and the reverse/forward dns on the primary ip address. When the email arrives, is read, or is replied to it does give the domain hosted as the reply to address. But if you look in the headers for the email you will see your server's name as defined in your SMTP server in there as the relay. I would also recommend point mail.allofyourclientsdomains.com to the primary ip address with the servername, so when you add SPF records (see below) they actually take effect properly. From your house, or a site that is not located or using the nameservers of your server do an nslookup on the ip address to verify that the reverse dns is setup properly. Then do an nslookup on the forward dns that was given as a result from the reverse dns lookup, the forward should match the reverse. servername.site.com -> 1.2.3.4 1.2.3.4 -> servername.site.com For your clients DNS make sure you have SPF and DKIM records setup, this will help you a heap. These require additional dns adjustments. Some recommended reading: http://www.openspf.org/ http://www.dkim.org/
i dont think you can host multiple mail servers on a single box unless you configure VMs in it. Use exim, it is the best. Also make sure that you have your SPF and rDNS records in place. Validate your emails and make sure that the bounces are minimal. Anyways, now that you are blacklisted, it is best that you get a new set of IPs.