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All you have to do is properly configure MX records. If you have standard MX configuration in place then probably following configuration should be sufficient to achieve what you want: Add new records, e.g: mailer.mydomain.com IN MX 1 ASPMX.L.GOOGLE.COM mailer.mydomain.com IN MX 5 ALT1.ASPMX.L.GOOGLE.COM mailer.mydomain.com IN MX 10 ...


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If your mail server is running on mygreatdomain.com - it's going to have the same IP 999.999.999.999 as your domain. When someone emails you@mygreatdomain.com it will look for your MX records, if no MX records are found it will use your A record to send the mail to. So you don't need an MX record, since you're using the same IP. Since you're learning, ...


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To cite RFC 1035, the MX record contains two values: PREFERENCE A 16 bit integer which specifies the preference given to this RR among others at the same owner. Lower values are preferred. EXCHANGE A which specifies a host willing to act as a mail exchange for the owner name. ...


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You can combine them all like this. v=spf1 a mx ptr ip4:x.x.x.x ip4:y.y.y.y include:mktomail.com include:icpbounce.com include:spf.mandrillapp.com -all I recommend changing the ~all to -all - the whole point in setting up authentication in the first place is to make it fail when it's violated. Then test sending emails from all the different places to ...


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The RFC's that specify how a MTA should handle MX records are RFC974, RFC1123 section 5.3.4, RFC2821 section 5 and RFC5321 section 5. RFC974 status is now HISTORIC. According to it, MTA's are expected to query the list of MX records associated to a domain and are "encouraged" to try all (or a fixed number of) SMTP servers, in ascending order of preference. ...


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The second setup doesn't support failover. Let's say mail.example.com has been resolved to 172.16.10.1 and it fails. Then 172.16.10.2 won't be tried as there is only one MX record. The third setup generates twice DNS traffic as the first one. Aside fom traffic, both of them have the same behavior: As you said some clients won't correctly do round-robin ...


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For failover do: example.com. 1200 IN MX 10 mail1.example.com. example.com. 1200 IN MX 20 mail2.example.com. mail1.example.com. 1200 IN A 172.16.10.1 mail2.example.com. 1200 IN A 172.16.10.2 The MTA will first try mail1, then mail2. Combining load-balancing and failover is ...


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In my opinion, your first setup is correct. The reasons are: You have 2 MX records with the same priority which is good for load balancing. RFC5321 states that SMTP-server needs to randomly distribute load for all servers have same priority As you mentioned, the round robin A record will not failover correctly. It's called multihomed-A record, sender will ...



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