Can someone help with FQDN?

[rusta]

I'm trying to setup a mail server from my home and it's actually working ok, but I want to switch over to a static ip. My ISP asked me to email them my FQDN.


How do I determine what my FQDN is?

For example if:

I have a domain "www.example.com"
I have MX record for "mail.example.com"
My server name is "123mail"
My server full name is "123mail.abc.local"


Would "mail.example.com" be the FQDN of my mail server?

 

[HillJack]

I have a domain "www.example.com"
I have MX record for "mail.example.com"
My server name is "123mail"
My server full name is "123mail.abc.local"


Would "mail.example.com" be the FQDN of my mail server?

mail.example.com could be your fqdn, but mail should be an A record, while (in this example) if your server is really called 123mail, then imo, 123mail.example.com should be the fqdn.

Keep in mind that you will need to create an A for 123mail.example.com too... Nothing like an invalid PTR for a mail server.

 

[DelJo63]

Hilljack is correct.

Remember, your email server (to be of any real value) must be accessible to
the Internet. While you can rename it anything you like on the internal LAN
(eg 123mail.abc.local), that is basically the wrong thing to do; use one name for
each resource.

Stick with your domain www.example.com; your local DNS should be the one
to map the email server into a location ip address using 123mail.example.com as
the name to some system in the DMZ or behind the infrastructure firewall on your lan.

 

[rusta]

Thanks HillJack and jobeard, I appreciate the help. I think I understand it better now, but not sure. Have a few more questions if you have the time.


jobeard what do you mean by

While you can rename it anything you like on the internal LAN
(eg 123mail.abc.local), that is basically the wrong thing to do; use one name for
each resource.
Stick with your domain www.example.com; your local DNS should be the one to map the email server into a location ip address using 123mail.example.com as the name to some system in the DMZ or behind the infrastructure firewall on your lan.

Should I rename my mail server machine from "123mail" to "example" ? What do you recommend?

Is a PTR record necessary? I thought that a MX record was all I needed.

The reason I ask is becasue I have the mail server setup now and seems to be working ok and as far as I know there were no PTR records created.

Here is some more info

I have a SBS 2003 and Exchange setup. 1 NIC with local router. There is 1 website hosted on it. Exchange is setup to use my ISP's email sever as smarthost. If I want to use OWA, I type in hxxps://mail.example.com/exchange. If I use an email client, I use mail.example.com for both incoming and outgoing servers. This works ok, but I had to change the default SMTP port number from 25 to 587.

I know this is not the correct way to set it up, that's why I am getting a static IP with no ports blocked.
The goddady settings below are probably not correct either.

According to what HillJack said, I should add another A record for 123mail.example.com.
Host=123mail
Points To=146.xxx.xxx.xx
Would this be correct?


Below is my settings on godaddy.

A (Host)

Host Points To
@ 146.xxx.xxx.xx
mail 146.xxx.xxx.xx


CNAMES (Aliases)

Host Points To
mobilemail mobilemail-v01.prod.mesa1.secureserver.net
pda mobilemail-v01.prod.mesa1.secureserver.net
email email.secureserver.net
e mail.secureserver.net
webmail webmail.secureserver.net
pop pop.secureserver.net
smtp smtp.secureserver.net
www @
ftp @


MX (Mail Exchange)

Priority Host Goes To
0 @ mail.example.com


Nameservers

NS33.DOMAINCONTROL.COM
NS34.DOMAINCONTROL.COM

 

[DelJo63]

I'm validating Hilljack's comment; 123mail.example.com would be fine while
123mail.abc.local is nonsense.