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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical An A record is an MX record and is a missing MX....
Please forgive if this has been discussed, beaten, or decided previously here on the list. A recent issue I encountered has prompted me to ask the following question. What I am looking for is clarification regarding the "proper" way of implementing Mail Exchange records, etc. I have always been under the impression (or taught at least) that an MX record was necessary (required) for mail exchange. I at least believed that this was the correct way. Recently, we implemented a new mail server at our facility and started having some issues relaying mail to a few domains. Although this has already been resolved, I was under the impression that these two domains where the actual problem since I could not resolve an MX record for either one. Since then I have learned that some MTA's will look for an A record if it cannot find an MX record and use the A record instead. Is this acceptable (in a "best case scenario") as a correct method? Obviously some admins I have encountered are starting to host mailservers for sub-domains and domains without MX entries on their DNS zone records. Relying on the A record alone. Gerardo A. Gregory
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