Re: General Question

  • From: budiyanto <budiyanto@xxxxxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Tue, 5 Mar 2002 15:35:12 +0700

Does your mail server have a permanent connection to internet? If it does,
you won't have that many troubles. If it uses dial up, it is better and
safer to use the popular pop3 mailbox hosted in internet to pull down
messages, I think. Anyway, here's a little something you should consider
about before you configure your IMC, quoted from:

SMTP ETRN was developed as an after thought to allow the SMTP protocol to
work over dial-up connections. ETRN is a signal sent to your ISP to tell it
that you are connected to the Internet and can receive messages. Microsoft's
Internet Mail Service only supports ETRN for dial-up connections. Exchange
POP3 was created to better serve the dial-up Exchange community using the
much preferred POP3 protocol. The following is a list of problems when using

ETRN requires a costly permanent (static) IP address 

Although you do not use a permanent connection to the Internet, SMTP can
only send to permanent IP addresses. Your ISP still assigns (and charges)
you a permanent IP address even though you use it intermittently. 

POP3 can use an inexpensive dial-up account where your IP address is
assigned dynamically. 

Erroneous delayed transmission reports 

Because SMTP assumes a continuous connection to the Internet, it expects to
be able to send you its messages without any delay. If you use ETRN and are
not connected to the Internet your ISP's SMTP server will still try and
connect to your IP address which will in most cases will not be available.
The server will save the message and retry later but will send the sender of
the message a problem report saying the message's delivery is delayed. 

POP3 mailboxes at your ISP are always available to receive messages and
therefore will never be delayed. 

ETRN is difficult to configure 

ETRN requires extra configuration on the ISP's servers for each new customer
and is not widely supported by all ISPs. This is another reason why this
method is more costly. 

POP3 accounts are available from all ISPs with little effort and cost.
Because Exchange POP3 works with all ISPs you have the ability to choose the
best ISP for your needs and budget. 

ETRN is a security risk 

Because ETRN requires a static IP address it is easier for a hacker to
attack your network knowing that when you are connected your IP address is
always the same. 

POP3 dial-up accounts are assigned a different IP address everytime they
connect and do not give a hacker enough time to attack your network.

-----Original Message-----
From: Uma kumar [mailto:kumar@xxxxxxxxxxxx] 
Sent: Tuesday, March 05, 2002 11:48 AM
To: [ExchangeList]
Subject: [exchangelist] Re: General Question

Hi Rajesh

Yes it can b done
What  you need to do is ask your ISP to add an MX record pointing to the
your public ip given to the server and install Internet mail service (IMS)
in that add you domail name to inbound.

good luck


----- Original Message -----
From: "RAJESH.K.R." <san_rajesh@xxxxxxxxx>
To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
Sent: Sunday, March 03, 2002 9:16 AM
Subject: [exchangelist] General Question

> Hi everybody,
> I just wanted to know if it is possible to have exchange server configured
> to receive mails from outside (Not just inside the LAN) without having a
> mailbox with the ISP. This question may seem so stupid but my boss wants a
> written proof of the same. Hope somebody gives a detailed reply to this
> question at the earliest.
> I repeat my question - Is it possible to have exchange server configured
> receive mails from outside (Not just inside the LAN) without having a
> mailbox with the ISP. I have a public IP address & a domain name as well.
> Will this be enough to configure - or I need a mailbox from the ISP.
> Thanks,
> Rajesh
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