[AusNOG] PTR Records

[David Beveridge]

On Tue, Nov 18, 2014 at 1:47 PM, Scott Howard <scott at doc.net.au> wrote:
> On Mon, Nov 17, 2014 at 6:18 PM, David Beveridge <dave at bevhost.com> wrote:
>>
>> And for the record, yes, the EHLO header was mycompany.com.au and it
>> does have a normal A record.
>
>
> In that case, whilst your provider isn't correct - it's probably a good idea
> to listen to them.
>
> Having an email server with the hostname example.com is legal, and in that
> case you would want to PTR record to go to the same hostname - but it's a
> really bad idea.
>
> Like it or not, example.com has become synonymous with www.example.com, so
> the expectation is that you'll have a web server running on example.com.
>

>From an SEO point of view it is very bad to have two identical web sites on
both example.com and www.example.com,  Therefore I normally would have
a http redirect on example.com to www.example.com.

The other bonus, is that when you register a SSL Certificate for
www.example.com,
it will often have a SAN for example.com, so you can use the same
certificate on
the web server and the mail server, even if they're on separate IP addresses,
in different physical locations.

> Now, perhaps your web server is on the same IP as your email server (or
> perhaps you don't have a web server today?!) - but why lock yourself into a
> naming scheme when there's no need to do so. Having example.com and
> mail.example.com (or even fred.example.com if you don't like using generic
> names) on the same IP might sound like a little bit more work today, but the
> day that you decide to move your webserver somewhere else you're going to
> appreciate having done it that way.
>
>   Scott
>