PIX and Microsoft Exchange

Hi!

I have a problem in my setup with my PIX firewall and Microsoft Exchange.

I have a pix515 UR with an Outside, DMZ and Inside interface. The config is as follows:

Outside
- no servers on the outside

Dmz1
- WinNT 4 - Microsoft Exchange

Inside
- WinNT 4 - PDC
- Outlook clients

When I recieve a mail, Outlook normally would say \"You have new mail\", but I have to manually check for mail myself in order to get mail. This is because the PIX dosen\'t allow the Exchangeserver to make connections to the clients on the inside. My question is how I allow that so my users won\'t have to manually check for mail all the time. Below is a list of commands that I have tried to enter into the PIX.

name 129.142.128.230 mailserver_outside
name 192.168.0.21 mailserver_dmz1
name 192.168.0.20 pdc_dmz1
name 192.168.100.20 pdc_inside

conduit permit tcp host mailserver_outside eq smtp any

conduit permit tcp host pdc_dmz1 eq 139 host mailserver_dmz1
conduit permit udp host pdc_dmz1 eq netbios-ns host mailserver_dmz1
conduit permit udp host pdc_dmz1 eq netbios-dgm host mailserver_dmz1

static (dmz1,outside) mailserver_outside mailserver_dmz1 netmask 255.255.255.255 0 0
static (inside,dmz1) pdc_dmz1 pdc_inside netmask 255.255.255.255 0 0

I sure hope somebody can help me. I\'ve visited Ciscos homepage and they explain something about having 2 Winnt servers and they also use Wins, but their example does not include a DMZ. I would prefer NOT using Wins, since I don\'t no much about it.