PIX 501 and Exchange

[cyberfreek]

Hello.

My configuration has been working some time now. But now that I attempted to configure a Microsoft Exchange server 2000 with the pix, I can't seem to get it to work.

I have 5 ips to work with, one which is used for E0 and the other 4 are used in the pool. From what I understand is that ips in the pool will allow outbound traffic based on how many ips are int he pool. If this is true, how can I configure the pix so one ip will be used for E0, another for the Exchange mail and the inside workstations will have access to the outside world? Please forgive me for I am a novice and what I'm writing may not make sense. Below is my current configuration. Thank you. Your help is much appreciated.

Result of PIX command: "sh config"

: Saved
:
PIX Version 6.1(3)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd WSgPDQg.Vy73lhFZ encrypted
hostname pixfirewall
domain-name ciscopix.com
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060
fixup protocol skinny 2000
names
name 192.x.x.x UserName
access-list 100 permit icmp any any echo-reply
access-list 100 permit icmp any any time-exceeded
access-list 100 permit icmp any any unreachable
access-list 100 permit gre any any
access-list 101 permit ip 192.x.x.x 255.255.255.0 192.x.x.x 255.255.255.0
access-list nonat permit ip 192.x.x.x 255.255.255.0 10.0.0.0 255.255.255.0
access-list nonat permit ip 192.x.x.x 255.255.255.0 192.x.x.x 255.255.255.0
access-list acl_out0 permit gre any any
pager lines 24
logging on
logging buffered errors
logging trap notifications
logging history notifications
interface ethernet0 10baset
interface ethernet1 10full
mtu outside 1500
mtu inside 1500
ip address outside 67.x.x.x 255.255.255.248
ip address inside 192.x.x.x 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
ip local pool pptp-pool 10.0.0.1-10.0.0.5
pdm location 192.x.x.x 255.255.255.255 inside
pdm location 192.x.x.x 255.255.255.255 inside
pdm location 67.x.x.x 255.255.255.255 outside
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 67.x.x.138-67.x.x.141
global (outside) 1 interface
global (outside) 1 67.x.x.x
nat (inside) 0 access-list nonat
nat (inside) 1 192.x.x.0 255.255.255.0 0 0
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
access-group 100 in interface outside
route outside 0.0.0.0 0.0.0.0 x.x.x.142 1
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
http server enable
http 64.x.x.0 255.255.255.0 outside
http 192.x.x.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
no floodguard enable
sysopt connection permit-ipsec
sysopt connection permit-pptp
no sysopt route dnat
crypto ipsec transform-set tm1 esp-3des esp-md5-hmac
crypto map xxxx 1 ipsec-isakmp
crypto map xxxx 1 match address 101
crypto map xxxx 1 set peer 67.x.x.x
crypto map xxxx 1 set transform-set xxxx
crypto map xxxx interface outside
isakmp enable outside
isakmp key ******** address x.x.x.x netmask 255.255.255.248
isakmp identity address
isakmp policy 1 authentication pre-share
isakmp policy 1 encryption 3des
isakmp policy 1 hash md5
isakmp policy 1 group 1
isakmp policy 1 lifetime 1000
telnet 192.x.x.x 255.255.255.255 inside
telnet timeout 5
ssh timeout 5
vpdn group 1 accept dialin pptp
vpdn group 1 ppp authentication pap
vpdn group 1 ppp authentication chap
vpdn group 1 ppp authentication mschap
vpdn group 1 ppp encryption mppe auto
vpdn group 1 client configuration address local pptp-pool
vpdn group 1 pptp echo 60
vpdn group 1 client authentication local
vpdn username xxxxx password xxxxx
vpdn enable outside
dhcpd address 192.x.x.20-192.x.x.30 inside
dhcpd dns 63.200.115.40 206.13.31.12
dhcpd wins 192.x.x.x
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd auto_config outside
dhcpd enable inside
terminal width 80
Cryptochecksum:c418e90d72ad668b960b1f451

 

[themut]

You need a static translation for exchange:

static (inside, outside) <exchange-public-ip> <exchange-private-ip> netmask 255.255.255.255

Then you need to allow SMTP traffic on your acl 100:

access-list 100 permit tcp any host <exchange-public-ip> eq 25

Since you are using exchange, you will also need to disable fixup protocol smtp.

 

[cyberfreek]

themut

Thanks for the info. That will definitely help me out.
I'm confused on one thing. Doesn't PAT work in a way that the private addresses are translated to the addresses in the pool which are 4 addresses and if there are more that 4 workstations, they would not have access to the internet because of the limit? If this is true, I would not be able to create a static translation for the Exchange server because I no longer have additional ips. Am I making sense?

 

[themut]

Your using both dynamic NAT and PAT which means users will use the pool (67.x.x.138-67.x.x.141) of IP addresses to go out to the Internet. Once this pool is fully used, internal hosts will use the PAT address to go out to the internet and in theory it can handle up to 64k connections. You need to remove one IP address from the pool and assign it to the static translation needed.

 

[cyberfreek]

Ah! That makes sense. I will give that a try in the next hour and let you know. Will you be available? You have responded promptly and been very helpfull.

Thank again and I willbe emailing you soon.

 

[cyberfreek]

Oh I forgot. Is there any thing else I need to do? My exchange server will also be the DNS server with the MX record.

 

[tpulley]

You didn't say if your DNS server is strictly for internal users or for external (Internet) users. If Internal, nothing else need be done. If external you would allow port 53 (udp) Similar to what the Mut mentioned above.

access-list 100 permit udp any host <exchange-public-ip> eq 53

 

[cyberfreek]

OK. I'm almost there. The customer's current email service has added an mx record to point to 67.119.89.138 > tml01.trinitymortgageloans.com.

I am now able to send outbound mail but not able to receive inbound mail. Any suggestions.

 

[tek777]

maybe you need a rule to bypass nat?

 

[cyberfreek]

tek777

Thanks for the suggestion. I just resolved my problem.

All that was left to add was a static route.
static (inside,outside) <PublicIP> <PrivateIP> netmask 255.255.255.255 0 0

I am still not able to recieve inbound emails but I'm able to ping the outside address and telnet to port 25. I may just have to wait for the DNS updates.

I am learning so much from you guys. A little slow but I'm getting there.

Thanks to all of you.