Configuring a mail server – How to inbox?

Ariel Luduena Karhs
February 16, 2009 | 3 min read

spamMany people think that configuring a mail server is a trivial task … you think the same? don’t be so sure…
I remember my thoughts… “I want to inbox !! why are the mails arriving to the junk folder?? I’m not a spammer”

The truth regarding this, is that we do not have a unique technique or way to inbox in the different mail servers (hotmail, yahoo, gmail, aol, etc), because these mail servers have different security protocols (SPF, Domain Keys, Sender ID?…) and each has it’s particular tricks.

The first step is to make sure that  all the DNS stuff is configured properly. Some mail servers can send mail from multiple IP addresses at the same time, so, you must determine the IP or IPs that you want to use to send emails.  Once you have identified this IPs, you must view their rDNS configuration (Reverse DNS) .  You can do this executing the following command:

host -t PTR

After executing the command you will look at somthing like this: domain name pointer

The sentence in bold above must point to the mail server! (Obviously the first time it will point to some place that you don’t know, commonly a temporary hosting domain. Every mail server has a name (machine name) and the rDNS must point to that name. ( for example)
To configure the rDNS in a correct way, you must submit a ticket to the hosting that manages your server (the IP owner) and ask for this change.
Once this change is done, you must wait 12-24-48 hours (propagation time) and test again.

The rDNS setting is a very important thing, almost all mail servers have this validation. For example, if this configuration is wrong when you are trying to send mails to hotmail,  your mail is discarded and doesn’t even go to junk folder.

How to inbox in hotmail?

To inbox in hotmail, you must implement the SPF validation(more details). The truth is that hotmail, has a security framework called Sender ID that is based in SPF and the configuration is the “same” (Sender ID has other features that you can use).
The first step is create a SPF record and with this wizard it is really easy.

The SPF record is a string line like this:  v=spf1 ip4: mx a ~all  (Twitter SPF configuration)

Basically in the record you have to specify wich IP or IPs can send emails using your domain.

Once you have your SPF record, you must publish this record in your DNS server. If you use a DNS server provided by for example (or another hosting/server provider), you will have a tool inside your console that lets you enter your SPF record. Anyway, if you don’t find the tool, submit a ticket to your provider!
If you have a DNS server, you must put the SPF record inside the configuration file of your domain. ( for example).  (If you have a DNS server, I’m sure that you know what I mean.)
In this configuration file you must add a line like this: IN TXT ” v=spf1 ip4: mx a ~all”… that’s it.

To test if your SPF record is published, you can go the wizard that I use above and put your domain name. In the step 2, if you have a SPF record, the wizard will display it to you.
Another way to test your SPF record, is use this tool that I found .. it’s really good.

How to inbox in yahoo?

To inbox in yahoo you must configure Domain Keys. I will write about this configuration (or maybe my friend Gian) in a few days.

I hope this helps you with your problems 🙂

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