Domain Mapping A Record vs Cname Dedicated IP Clarification

This question is more of a clarification request than troubleshooting. Any insight and expertise in this area is much appreciated.

Domain mapping allows for an end user to map their TLD to their multisite blog installation.
This is generally allowed through the use of A Record in their domain registrars information.

Cname can be used, but registrars like GoDaddy, do not allow TLD example.com to be mapped to a cname, only to an IP. http://www.example.com can be mapped to a cname record, but example.com requires an IP address.

I have been desiring to have all my members map their domain address using a cname or name server to allow for flexibility in future server upgrades or migration.
The issue with this method is 2 fold.
1. Cname usually takes away MX records, so if they have email hosting through their domain registrar it gets misconfigured.
2. nameserver mapping requires I map their domain manually in my cpanel / dns. Additionally as the above, if they have email hosting through their registrar this gets misconfigured (I guess I would have to manaully remap their MX records to their email provider in this case?)

So that being said, is this the nature of domain mapping? that only A Record using the server's IP address can be used for a TLD (example.com)? and at that the IP address must be dedicated for each multisite installation.

Thank you all if you have any other advise on how to accomplish TLD mapping without IP address, and while retaining the domain registrars Mail Server configuration, let me know.

My hosting provider, although I am very pleased with, seems to also be a bit hesitant to grant me my alloted dedicated IP as them being rare and highly valued, so if I can manage to not rely on that it would be much more freeing of a configuration.

Best Regards,
RaMaEl

  • Michelle Shull

    Hello, RaMaEl!

    In my experience, everything related to DNS is 10x more complicated than it needs to be. But! We can suss this up. To address your points one-by-one:

    1. You're correct, A records are typically used for TLDs, and CNAME is used for sub-domains. This means, usually, CNAMEs and MX records can't co-exist without causing problems.

    2 The work around is usually to map the MX record to an IP address, which you can see explained in great detail here: http://joshstrange.com/why-its-a-bad-idea-to-put-a-cname-record-on-your-root-domain/

    3. Cloudflare has recently introduced CNAME flattening as part of their service (read here: http://blog.cloudflare.com/introducing-cname-flattening-rfc-compliant-cnames-at-a-domains-root) but that also maps to an IP.

    4. If you paid for dedicated IP addresses, your host should be giving them up, they're not THAT rare, but that's just this woman's opinion. : )

    So, long story short, mapping to an IP is the best way to get CNAME to play nicely with MX.

    On a more personal note, this is why I started using Gmail with my domain name to handle email, instead of having to reconfigure the whole thing every time I moved servers. There are also services which can provide JUST email, pointing your MX records there instead of your server can save a LOT of resources, as well as make your domain mapping much simpler. Just an idea, but if that's something you'd like to explore, I've just been through it, and I'd be happy to walk you through.

    Hope this is helpful! Have a great Friday.

  • Sacred Website

    Thank you Michelle for all this information,
    Cname flattening seems to be what I would have wanted as a resolution. This unfortunately would not be convenient as it is not a common feature of domain registrars, and would mean that the end client would require signing up for a cloudflare account and THEN mapping their apex / root domain to my server cname. which really is way more complex for most of my expected users. But its nice to know it exists. I imagine this is a need that is more global as the technology as a whole of dns gets updated maybe (I know VERY little about it, but just the cname apex mapping seems to be the limitation in my need).

    So it seems that I either accept the fact that my users will have to map their A record to a dedicated IP, and if the need to migrate does ever occur in the future, we would implement a migration strategy / phase.

    Or I would encourage nameserver mapping of their domain to my server, which is not desirable unless I am willing to either host the email server, or repoint the MX records individually back to the user's domain registrar or mail server of choice (too much manual input on my side).

    Does this seem correct to whoever?
    Am I missing anything here? should I just accept that using a dedicated IP A record on the domain registrar for my multisite users is really my best bet with the only downside being manual remapping for any future migration IP address change?

    Thank you again for assisting me in verifying my choices as I move forward in my deployment process.

    Best Regards,
    Ramiel B

  • Michelle Shull

    Hello again, Ramiel!

    If it were my network, I would stick to mapping A records to dedicated IPs, since it should work with the least trouble/effort/third parties of your options, and if/when you do decide to migrate, you'll have much less to reconfigure at the new home.

    CloudFlare is becoming a lot more pervasive, I think even the newest of the webmastering newbies will be using it without confusion in the next couple of years. They also tend to be right on the cutting edge, so if they demonstrate a lot of success with cname flattening, that may very well trickle down to hosts who are paying attention.

    Take care!

Thank NAME, for their help.

Let NAME know exactly why they deserved these points.

Gift a custom amount of points.