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I have just taken ownership of a domain which had a couple of associated email addresses. I have left the mail boxes with the previous host, and so have been looking at updating the MX records in my domain registrar to forward the incoming/outgoing mail.

I have seen that some people setup an A record for mail. which points to the IP of the mail server. However, the instructions I followed only mentioned adding the 3 MX records with different priorities.

Without the mail subdomain set up, what do I use as the server name when connecting via iPhone and Outlook? As this was previously mail.domain.com

Thanks,

C Shelton
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    I'm not entirely sure what you're trying to ask. The mail server doesn't need to be named "mail", but it does need to have _some_ name. [MX records must point to a name, not directly to an IP address](https://serverfault.com/q/663112/126632). It's also not clear why you have three of them. If you only have one mail server, you need only one MX record. – Michael Hampton Oct 22 '18 at 22:53
  • Hi @Michael Hampton I was told by the previous manager of the domain. This domain, as well as website and mail were all hosted on one account. I have decided to leave mail where it is, but take ownership of the domain and web hosting. They advised me to ensure I add 3 MX records which should forward mail traffic and allow mail to continue as normal. They follow the format mx10.something.com etc. I have added these, but it's not clear to me if I need to add anything else in for email clients to connect? Previously the SMTP server was mail.domain.com. But I have no mail DNS entry. – C Shelton Oct 22 '18 at 23:17
  • If your mail is hosted by a third party outside your domain, then you might not have a `mail` name in your domain at all, and that's perfectly fine. – Michael Hampton Oct 23 '18 at 02:18
  • It is yes. So when connecting from an email client, the SMTP server my just be domain.com? – C Shelton Oct 23 '18 at 05:49
  • If your email is hosted by a third party, the SMTP server name is set by that third party. The name usually is not in your domain, but their domain. They can allow you to "white label" the name by providing you a sample DNS record (usually a CNAME) to add to your domain, but this isn't strictly necessary. – Michael Hampton Oct 23 '18 at 13:37

2 Answers2

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The convention to use mail.domain.com is becoming a standard because of some non technical's points too;

  • Often mail server can be setup for OWA or remote mail navigation in a browser. As such it's easy to tell a user to navigate to mail.domain.com for that purpose.

  • If you use multiple web service and have a router that allow it, using a dedicated name for the OWA will allow you at the router level to process inbound NAT rule for the web service that will redirect to the correct web server depending on the domain name the user is requesting.

You could use any entry in your MX record, but using mail.domain.com is convenient to say atleast for a end user view.

yagmoth555
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  • Ok so if I was to use mail.domain.com how would I set that up? Would I create an A record which points mail to the IP of the mail server? And then point my MX to mail.domain.com? – C Shelton Oct 23 '18 at 05:51
  • I have been provided 3 different MX values based on priority. Would I just choose one arbitrarily? Would I then lose the ability to prioritise the MX values? – C Shelton Oct 23 '18 at 09:33
  • @CShelton I would create that A record, that point to the MX, but for MX priority, do you got multiple WAN IP or a reason to use 3 MX record ? If no I would only use one. – yagmoth555 Oct 23 '18 at 16:02
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When you connect with iPhone or Outlook, the MX records don't matter. You can use any name for the mail host(s) (incoming and outgoing), or you can omit names and enter IP addresses directly (not recommended).

The MX records are needed for the server to receive emails from the outside. The MX records must point to valid A records.

If your instructions mention adding 3 specific MX records, then the A records for these three names already exist and your provider has already configured these mail servers to accept emails for your domain. Your provider should also have given you the names to use for incoming and outgoing servers (POP/IMAP and SMTP).

If you have your own mail server, you must create an A record that points to the mail server and a MX record that points to the A record, and you have to configure the mail server. But then you wouldn't have instructions mentioning 3 MX records.

RalfFriedl
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  • Hi @RalfFriedl thanks for your reply. I see, so when you see mail.domain.com is that just a convention that's worth following? Yeah so my MX records don't point to an A record, they point to the server which I was told. So if these A records already exist, where will they exist? As I don't have anything in my DNS which, apart from these MX records, relating to mail. – C Shelton Oct 22 '18 at 23:06
  • Having mail.domain.com is common but not necessary. There may be reasons to use other names. The names you were given for the `MX` records should point to `A` records, otherwise you won't receive mails. The names should be servers from your mail provider, not names in your domain. – RalfFriedl Oct 22 '18 at 23:19
  • The MX records point to the mail server, and different slightly with priority. mx10.example.com for example. So this should be enough? – C Shelton Oct 22 '18 at 23:22
  • You can query the three names you have for `A` records, you should get at least one `A` record for each of the names. – RalfFriedl Oct 22 '18 at 23:33
  • Correct, I queried the 3 names and they do have an associated A record. With regards to email clients, what SMTP sever name should be used, as this was previously mail.domain.com? Would it now be just domain.com? – C Shelton Oct 22 '18 at 23:41
  • So your provider, who gave you the names to use, has already set up the `A` records for these names (as they should), and you just have to point your `MX` records to these `A` records. – RalfFriedl Oct 22 '18 at 23:47