You could try an all-in-one solution like iRedMail[0] or Mail-in-a-Box[1]. Those supposedly do most of the leg work for you and set up a commonly used stack (Postfix, Dovecot, SpamAssassin, Roundcube, etc). I've never used either of them since I just install everything piecemeal, but I imagine there is an ease of use tradeoff compared to setting the same stack up yourself. In other words, it'll be easier to set up initially, but the downside is that you wont learn the ins and outs of the individual components. So if something breaks or you need to make an adjustment you're going to have a more difficult time at that point.

That said, there are some things you should be aware of when running a mail server:

1. You need to make sure that the IP address and domain name that SMTP is bound to is not on a blacklist[2]. You also need to consider the trustworthiness of your host because you could very well get caught in the cross-fire if one of their other customers gets them range banned. Certain cloud providers that make it very easy to change IP will more than likely have all of their addresses on some blacklist or another.

2. You also need to make sure you have matching forward (A record) and reverse (PTR record) DNS records for that IP address. This is called Forward-confirmed reverse DNS, aka FCrDNS. Many mail servers will reject email from servers that do not have or have mismatching records for FCrDNS.

3. You must set up SPF and DKIM. Many mail servers will either reject mail from servers without these, or at least weight heavily against it.

4. You probably want to make sure TLS is set up properly, otherwise your mail is going to travel the internet in plaintext.

5. The IP address you're sending from is going to start off with no reputation. The volume, type of mail, and how many people mark your mail as spam is going to decide whether other mail servers start filtering you or not. You may have no problems here. If you're unlucky, you will need to try to reach out to whichever major mail provider is filtering your mail. Many of them have a ticketing system for this, but you'll be at the mercy of whomever is working that ticket. There are also various whitelists that might be worth trying your server on. They're usually very selective and will probably reject your request.

6. You really, really need to make sure you've got your policies set up correctly because you do not want to accidentally set up an open relay[3] that will be used to spam other people.

7. Greylisting is a very, very effective means of spam filtering. The downside is that mail from new servers wont be delivered instantaneously and will instead be delivered whenever their mail server tries to deliver it again. Other than that, most spam is malformed in some way so some basic DNS checks will filter a ton of it. There are also free RBL and DNSBL lists that will pick up the slack.

[0] http://www.iredmail.org/ [1] https://mailinabox.email/ [2] https://mxtoolbox.com/blacklists.aspx [3] https://en.wikipedia.org/wiki/Open_mail_relay

user:	Lan
created:	November 2, 2010
karma:	57