SMTP Mail Delivery ! Help

[LOSTBALL]

Hi all,

I am quite new to these cisco firewalls so I hope someone can help. I have setup a new Cisco 506E firewall and I have a problem with SMTP mail delivery. I can send mail out but mail delivery is being block. E-mail is delivered to the external interface of the firewall and I want to create a tunnel to deliver the mail to the internal mail server on our private network. I have include my current config below.

I hope someone can figure out what I am doing wrong or possible some pointers.

Thanks.



PIX Version 6.3(1)
interface ethernet0 auto
interface ethernet1 auto
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password xxxxxx xxxxxxxx encrypted
passwd xxxxxxxxxx.xxxxx encrypted
hostname CISCO506
domain-name viper.com
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol ils 389
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
fixup protocol smtp 25
fixup protocol sqlnet 1521
names
object-group service smtp tcp
port-object eq smtp
access-list inside_access_in permit udp any any eq domain
access-list inside_access_in permit tcp any any
access-list outside_access_in permit tcp any host xxx.xxx.xxx.217 eq smtp
pager lines 24
logging on
mtu outside 1500
mtu inside 1500
ip address outside xxx.xxx.xxx.217 255.255.255.248
ip address inside 192.168.10.74 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
pdm location 192.168.10.1 255.255.255.255 inside
pdm location xxx.xxx.xxx.217 255.255.255.255 outside
pdm location 192.168.10.30 255.255.255.255 inside
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
static (inside,outside) xxx.xxx.xxx.217 192.168.10.1 netmask 255.255.255.255 0 0

access-group inside_access_in in interface inside
route outside 0.0.0.0 0.0.0.0 xxx.xxx.xxx.222 1
timeout xlate 0:05:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 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
aaa-server LOCAL protocol local
http server enable
http 192.168.10.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-ipsec
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac
isakmp enable outside
telnet 192.168.10.30 255.255.255.255 inside
telnet timeout 5
ssh timeout 5
console timeout 0
dhcpd dns 212.23.8.1 212.23.8.6
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd auto_config outside
terminal width 80

 

[mdaddy]

Your outside access-list (the one specifying smtp) isn't applied using the access-group command and your static statement isn't right. Since you are overloading on .217 you need to specify a PAT statement that looks like this.

static (inside,outside) tcp xxx.xxx.xxx.217 25 192.168.10.1 25

you don't need to add the netmask statement on the end as the PIX will do this for you.

Hope this helps

 

[minxca]

Hi,
Don't forget to remove fixup protocol smtp 25

 

[LOSTBALL]

Hi mdaddy,
Thanks for the tip I have managed to clear the problem. Its been a good day. Also managed to get my VPN over GPRS to work after a few hassle, but thanks to good old debug icmp trace, I managed to find where the problem.


Hi winoto
What is the issue with the fixup smtp. I seem to have come across postings where some people say enable it, some say disable it. Any commen.

Thanks.

 

[mdaddy]

I wouldn't turn off the fixup, it works perfectly fine, when you are receiving directly from the internet. It provides great protection by filtering the port allowing only certain smtp commands to come through, if this firewall were separating lan segments with multiple other exchange servers/esmtp servers, it'd be a different story. Just my opinion, do whatever works best for you.

 

[yizhar]

HI.

> ip address outside xxx.xxx.xxx.217 255.255.255.248
> static (inside,outside) xxx.xxx.xxx.217 192.168.10.1
This is a conflict that will make problems in the future, so you should change it.
You can use different ip addresses, or switch to using "port forwarding", like this:
static tcp interface 25 192.168.10.1 25

Read more here:
Using nat, global, static, conduit, and access-list Commands and Port Redirection on PIX

http://www.cisco.com/warp/public/707/28.html

Yizhar Hurwitz

http://come.to/yizhar

http://teachers.sivan.co.il/yizhar