HELP: MS Exchange getting mail from Qmail and dialup ISDN.

HELP: MS Exchange getting mail from Qmail and dialup ISDN.

Post by Nick Mille » Sat, 24 Feb 2001 23:12:07



Hi everyone,

I have a friend who runs a small business, 2 years ago the had a network
setup by there local ISP/computer outfit. This place went bust about 2
months ago and the reconnected with another ISP and the've had no end of
problems. Their mailserver when down two days ago and the've asked me for
some help. Sorry for the long post and the crossposting but help is really
needed.

The network is all Windows NT based with an NT4.0 Server running Exchange
5.5.
Originally they had a linux box running RH5 (i think), called "mailserver",
connected to the network, which had a 3com ISDN TA connected to com1. The
3com TA would dialup to the ISP and stay connected permantently (and redial
if it lost connection). This provided the internet connectivity to the whole
network. The machine mailserver has a static IP address provided by the ISP.
The ISP provided DNS and had an MX record pointing to the ipaddress of
mailserver.

Up to here I understand but I don't understand the rest. On mailserver they
ran qmail, this was supposed to send and receive emails. From what I've been
told MS Exchange 5.5 on the NT server would get the mail from qmail on
mailserver and put it in users mailboxes. Exchange has Internet Mail Service
installed, but I don't know how this works.
Can someone explain to me how:
1. How does qmail process the mail for each user as it doesn't know the user
accounts?
2. Exchange gets the mail from qmail?

Now this worked up until two months ago, when they were forced to change
ISP's, the new ISP doesn't support linux and blames all the problems on the
setup, and have suggested they spend nearly $10,000 on a new ISDN Router and
Firewall appliance, being a small business in a country town, they really
cant afford this and don't have any other ISP choices in their area code.
After they connected to the new ISP the ISDN would disconnect every 2
minutes the ISP told them them the TA was faulty and ended buying a Nortel
Nautilus 200 ISDN router, the ISP hasn't sent anyone to install this yet,
although it arrived a week ago.

They have a spare computer a the office and I thought after looking at this
mess I could do a clean install on both the old mailserver and the spare
machine. Then reconfigure one to work like the old one did with qmail and
use the second machine as a firewall/proxy and connect the ISDN TA to that.
But I am unsure about how to do this could anyone help or point me to some
resources.

Any help would be greatly appriciated.

Nick.

 
 
 

HELP: MS Exchange getting mail from Qmail and dialup ISDN.

Post by Morga » Sun, 25 Feb 2001 04:59:53



> Hi everyone,

> I have a friend who runs a small business, 2 years ago the had a network
> setup by there local ISP/computer outfit. This place went bust about 2
> months ago and the reconnected with another ISP and the've had no end of
> problems. Their mailserver when down two days ago and the've asked me for
> some help. Sorry for the long post and the crossposting but help is really
> needed.

> The network is all Windows NT based with an NT4.0 Server running Exchange
> 5.5.
> Originally they had a linux box running RH5 (i think), called
> "mailserver", connected to the network, which had a 3com ISDN TA connected
> to com1. The 3com TA would dialup to the ISP and stay connected
> permantently (and redial if it lost connection). This provided the
> internet connectivity to the whole network. The machine mailserver has a
> static IP address provided by the ISP. The ISP provided DNS and had an MX
> record pointing to the ipaddress of mailserver.

> Up to here I understand but I don't understand the rest. On mailserver
> they ran qmail, this was supposed to send and receive emails. From what
> I've been told MS Exchange 5.5 on the NT server would get the mail from
> qmail on mailserver and put it in users mailboxes. Exchange has Internet
> Mail Service installed, but I don't know how this works.
> Can someone explain to me how:
> 1. How does qmail process the mail for each user as it doesn't know the
> user accounts?
> 2. Exchange gets the mail from qmail?

> Now this worked up until two months ago, when they were forced to change
> ISP's, the new ISP doesn't support linux and blames all the problems on
> the setup, and have suggested they spend nearly $10,000 on a new ISDN
> Router and Firewall appliance, being a small business in a country town,
> they really cant afford this and don't have any other ISP choices in their
> area code. After they connected to the new ISP the ISDN would disconnect
> every 2 minutes the ISP told them them the TA was faulty and ended buying
> a Nortel Nautilus 200 ISDN router, the ISP hasn't sent anyone to install
> this yet, although it arrived a week ago.

I'm probably not the best person to answer this, but I do know that
Exchange hates being knocked off the network now and then. It really
doesn't work well with dialup. You might consider just killing it and using
qmail for your mail server. Win clients can connect to it just fine.
-Morgan

"This is the day, your life will surely change"
-Matt Johnson

> They have a spare computer a the office and I thought after looking at
> this mess I could do a clean install on both the old mailserver and the
> spare machine. Then reconfigure one to work like the old one did with
> qmail and use the second machine as a firewall/proxy and connect the ISDN
> TA to that. But I am unsure about how to do this could anyone help or
> point me to some resources.

> Any help would be greatly appriciated.

> Nick.


--

 
 
 

HELP: MS Exchange getting mail from Qmail and dialup ISDN.

Post by Bryan Packe » Sun, 25 Feb 2001 13:51:02



> Up to here I understand but I don't understand the rest. On mailserver they
> ran qmail, this was supposed to send and receive emails. From what I've been
> told MS Exchange 5.5 on the NT server would get the mail from qmail on
> mailserver and put it in users mailboxes. Exchange has Internet Mail Service
> installed, but I don't know how this works.
> Can someone explain to me how:
> 1. How does qmail process the mail for each user as it doesn't know the user
> accounts?
> 2. Exchange gets the mail from qmail?

Qmail doesn't have to know about the users. They are just using qmail to
accept the mail from the outside and relay it in to the Exchange server.
The Exchange server then accepts it as regular inbound smtp.

For example, the MX record for the domain says to deliver mail for that
domain xxx.com to "mailserver". So the outside world sends all of it's
mail to that address. Somewhere Qmail has been configured to accept mail
for domain xxx.com, and then just turn around and relay it into the
Exchange server. It never checks usernames, it just blindly forwards all
mail for domain xxx.com to the NT box. I believe that can be either a
config setting in qmail or by using an internal DNS server which has the
MX record for xxx.com listed as the Exchange box. The Exchange server's
IMC just sees it as a regular inbound smtp transfer. The Exchange box
maintains the mailboxes and users. When users send mail out, the
Exchange servers IMC has been configured to deliver all external mail to
1 address, the linux mailserver, instead of the actual destination. When
qmail receives the outbound mail from the Exchange box, it uses DNS to
find the destination mailserver and delivers it the real destination.

Clear as mud, right?

hope that helps,
bryan

----------------------------------------------------------------------------------
Not one shred of evidence supports the notion that life is
serious.

 
 
 

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