Integration of Exchange Server and UNIX mail service




              +-----+                                        +-----+
              |     |                                        |     |
              |     |                                        |     |
  172.16.0.20 |     |                                        |     |
  ------------+-    | 192.168.0.5               192.168.0.3  |     |
              |    -+----------------------------------------+--   |
              +-----+                                        +-----+

OS:           UNIX (Linux, FreeBSD)                    Windows NT4 server


Software:    - firewall (kernel rules)                 - SP 6a
             - ucspi-tcp (http://cr.yp.to)             - Microsoft DNS service
             - qmail (http://cr.yp.to)                 - Microsoft Exchange 5.5
                                                       - SP 3 for Exchange 5.5

Config:      FQDN: border.domain.com                   FQDN: none
              IP 1:  172.16.0.20 - external             IP: 192.168.0.3
              IP 2:  192.168.0.5			

             /etc/resolv.conf
                    search domain.com
                    nameserver 192.168.0.3
                    nameserver 172.16.0.2



External DNS (172.16.0.2) provides: 
domain.com      MX preference = 10, mail exchanger = border.domain.com

domain.com      nameserver = ns1.my-ISP.com
domain.com      nameserver = ns2.my-ISP.com
ns1.my-ISP.com  internet address = 172.16.0.2
ns2.my-ISP.com  internet address = 172.16.2.2


Internal DNS (192.168.0.3) provides:
domain.com      MX preference = 5, mail exchanger = exchange.domain.com
domain.com      nameserver = exchange.domain.com
exchange.domain.com       internet address = 192.168.0.3



Microsoft Exchange Server 5.5 configuration:

- install Internet Mail Service (IMS) (Internet Mail Connector)
	- Open Microsoft Exchange Administrator
	- File -> New Other -> Internet Mail Service ...

- change properties of IMS as follow:
	- Routing: Reroute incoming SMTP mail 
		Sent to			Route to:
		domain.com		inbound

	- Connections: 
		Message delivery -> Forward all messages to host: 192.168.0.5

- stop and restart Microsoft Internet Mail Service



Qmail configuration:

border:~# cd /var/qmail/control
border:/var/qmail/control# ls -laF
total 8
drwxr-xr-x   2 root     qmail        1024 Jan  4 12:40 ./
drwxr-xr-x  10 root     qmail        1024 Dec 31 12:51 ../
-rw-r--r--   1 root     root           12 Jan  3 08:49 defaultdomain
-rw-r--r--   1 root     root           38 Jan  3 08:51 locals
-rw-r--r--   1 root     root           14 Dec 31 12:23 me
-rw-r--r--   1 root     root           10 Dec 31 12:23 plusdomain
-rw-r--r--   1 root     root           68 Jan  3 08:54 rcpthosts
-rw-r--r--   1 root     root           52 Jan  4 12:40 smtpgreeting
border:/var/qmail/control# cat defaultdomain
domain.com
border:/var/qmail/control# cat locals
localhost
border.domain.com
gw.domain.com
border:/var/qmail/control# cat me
border.domain.com
border:/var/qmail/control# cat rcpthosts
localhost
domain.com
border.domain.com
gw.border.com
border:/var/qmail/control# cat smtpgreeting
border.domain.com ... hi, did you study RFC 821 ?
border:/var/qmail/control#





Security issue: SMTP relay on the UNIX box:

- create the relay database for ucspi tcp-server:
	- create /etc/tcp.smtp plain text:
		192.168.0.3:allow,RELAYCLIENT=""
		127.:allow,RELAYCLIENT=""
	- create tcp.smtp.cdb:
		tcprules /etc/tcp.smtp.cdb /etc/tcp.smtp.tmp < /etc/tcp.smtp
	
- run qmail under ucspi-tcp using "-x /etc/tcp.smtp.cdb":
Insert 
     -x /etc/tcp.smtp.cdb
after tcpserver in your system boot scripts. The change will take effect
at your next reboot. 
If you make any changes to /etc/tcp.smtp, you must run 
     tcprules /etc/tcp.smtp.cdb /etc/tcp.smtp.tmp < /etc/tcp.smtp
again. You do not have to restart tcpserver. [1]


References: 

	[1]	qmail FAQ