sending email to xxx@SMTP_email_server_IP_address & registering MX / SMTP server addr


Hi

Pending the purchase of our domain,  I have already set up an
SMTP email server running postfix & this server has been given
a public IP address, say aa.bb.cc.dd

Q1
Can I test send an email to this server by sending to
a_postfix_mailbox@aa.bb.cc.dd ?

Q2:
Secondly after getting the domain, how do I link my SMTP server's
IP address so that it appears in MX record ?  The domain provider
I'm using is Adicio (it's just a website & we have to DIY, I'm not sure
if there's a support hotline to call)
sunhuxAsked:
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Ernie BeekConnect With a Mentor ExpertCommented:
Q1: Not really. You can test connectivity by doing a telnet from a remote location to aa.bb.cc.dd at port 25.

Q2: The domain provider (the one who manages your DNS) is the one who should create an MX record pointing to the public address of your mailserver (and perhaps a PTR record as well).
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sunhuxAuthor Commented:

Q1:
 I told my boss & the security guys that they have to permit SMTP (Tcp 25) to the whole
Internet & they insisted that since there's only a handful of organizations (about 5-6) that
send emails to my postfix/SMTP server, the firewall rule should be such that it permits
only those few organizations' SMTP servers to connect to my postfix server on Tcp25.
Looks like from your answer, email is relayed across several hops & it may be an SMTP
server that's totally unrelated to those organizations' (& their domains) that could be
connecting to my postfix server on Tcp 25, is this right?

Q2:
Out of curiosity, if the domain provider is running a DNS/BIND on a Linux box, what's
the commands that they would issue to get this done?
     
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Ernie BeekConnect With a Mentor ExpertCommented:
Q1: That could be the case. If they use a smart host for forwarding mail or use a hotmail/yahoo/gmail/whatever account, the ip addresses might vary and indeed be unrelated.

Q2: Phew, let me think.

The should set up a zone record something like:

$ttl 38400
yourdomain.com.    IN    SOA    ns1.yourdomain.com. webmaster.yourdomain.com. (
            1055026205
            6H
            1H
            5D
            20M )
yourdomain.com.        IN    A     1.2.3.4
ns1.yourdomain.com.    IN    A     1.2.3.4
ns2.yourdomain.com.    IN    A     1.2.3.5
yourdomain.com.        IN    NS    ns1.yourdomain.com.
yourdomain.com.        IN    NS    ns2.yourdomain.com.
mail.yourdomain.com.   IN    MX    1 yourdomain.com.
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RyanShaferConnect With a Mentor Commented:
Q1 smtp relays are typically used to relay mail from the edge of a network to the mail server which actually has a private ip on the internal network.  The smtp relay will still have the ip that the mail server is registered to. so the answer is no it cannot be accessed from anyone on the internet.

Q2

DNS records must be present within the zone and this is the syntax

mail.domain.com.    IN   A   aa.bb.cc.dd
domain.com.   MX  10    mail.domain.com.

10 is the priority number where MX record with lowest priority is chosen first.  Many mail servers will require you to create a PTR record as well.  this is done differenlt howver.
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sunhuxAuthor Commented:

Bear with me, one last question :

since my server's already been given a public IP address, how do I
assign this public IP address to the new domain I've just bought?
PTR record?  or how exactly is the DNS/BIND record being defined
(with a sample format of the record if possible)

Many thanks
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Ernie BeekConnect With a Mentor ExpertCommented:
Here we go:

yourdomain.com.        IN    A     1.2.3.4
www.yourdomain.com.    IN    CNAME yourdomain.com.

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sunhuxAuthor Commented:

and oh, someone from postfix list told me I can send test emails in advance
(prior to my domain being registered) by addressing the test emails to :
   recipient@[a.b.c.d]
where a.b.c.d is the public IP address of my SMTP/postfix server.

Well, gmail won't accept something with brackets in its "To: " field, & I
tested with Outlook webmail - those mails bounced with the message:
  recipeint@ (MOBILE:203126130167)
  To be able to send text messages, you need to set up your text messaging account.
  Click here to set up your account.
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Ernie BeekConnect With a Mentor ExpertCommented:
B.t.w. A PTR record is being used to do a reverse lookup, mostly used with mailservers to check if you really are who you say you are.
A PTR record is NOT being set up by the domain provider but by your ISP (so the one who manages your physical internet connection).
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sunhuxAuthor Commented:


Thanks Ernie.

So in your last reply 1.2.3.4 is the public IP address of my SMTP postfix server
or my webserver?  I don't have a webserver
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Ernie BeekExpertCommented:
I think you should also try that from a postfix server. That isn't a correct syntax when using anemail client.
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sunhuxAuthor Commented:

So I guess I don't have to do anything further about PTR record as my ISP
who assigned me the public IP address would have set up the PTR record
in the first place, is this right?
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Ernie BeekExpertCommented:
Ok, allready posted that before so i thought you wanted a web address as well.

Then it is:

yourdomain.com.        IN    A     1.2.3.4
mail.yourdomain.com.   IN    MX    10 yourdomain.com.
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Ernie BeekExpertCommented:
Depends, normally they night set up a PTR record but with a generic name. You would like it to point back at the domain you just set up.
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Ernie BeekExpertCommented:
night = might :-~
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sunhuxAuthor Commented:
'excellent
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Ernie BeekExpertCommented:
Thx.
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