Still can't receive email!

[mtnwinds]

Can you suggest what I have to do to be able to receive email? I can send fine but can't receive.

SBS 2000
int NIC 192.162.16.2 gtwy 10.0.0.2
ext NIC 10.0.0.2 gtwy 10.0.0.1

Cisco 802
eth 0 10.0.0.1
wan 67.x.x.x

I believe I have entered correct port forwarding via:
ip nat inside source static tcp 10.0.0.2 25 67.x.x.x 25 extendable

I can telnet into the domain from home using 67.x.x.x port 23 and config the router. I can't telnet into the domain if I select port 25.

Router config:
Current configuration:
!
version 12.0
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname xxxxx
!
logging buffered 8192 debugging
enable secret 5 $1$JV0M$eWjRkd9gcEgXuayGPtQtQ/
!
username xxx password x sssssssssssssss
!
!
!
!
ip subnet-zero
no ip source-route
!
no ip domain-lookup
isdn switch-type basic-ni
!
!
process-max-time 200
!
interface Ethernet0
ip address 10.0.0.1 255.0.0.0
ip access-group 121 in
no ip directed-broadcast
no ip proxy-arp
ip nat inside
!
interface BRI0
no ip address
no ip directed-broadcast
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-ni
isdn spid1 xxxxxxxxxxxxxxxxx
isdn spid2 xxxxxxxxxxxxxxxxx
ppp authentication chap pap callin
ppp multilink
!
interface Dialer1
description ISP
ip address negotiated
ip access-group 121 in
no ip directed-broadcast
no ip proxy-arp
ip nat outside
encapsulation ppp
no ip split-horizon
dialer remote-name Cisco1
dialer idle-timeout 300
dialer string 4571899 class DialClass
dialer string 3891311 class DialClass
dialer hold-queue 10
dialer load-threshold 10 either
dialer pool 1
dialer-group 1
fair-queue 64 16 0
pulse-time 0
ppp authentication chap pap callin
ppp chap hostname xxxxxxxxxxxxxxxxx
ppp chap password xxxxxxxxxxxxxxxxxxxxx
ppp pap sent-username xxxxxxxxxx password xxxxxx
ppp multilink
!
ip nat inside source list 18 interface Dialer1 overload
ip nat inside source static tcp 10.0.0.2 25 67.x.x.x 25 extendable
no ip http server
ip classless
ip route 0.0.0.0 0.0.0.0 Dialer1
!
!
map-class dialer DialClass
dialer isdn speed 56
access-list 18 permit 10.0.0.0 0.255.255.255
access-list 121 deny udp any eq netbios-dgm any
access-list 121 deny udp any eq netbios-ns any
access-list 121 deny udp any eq netbios-ss any
access-list 121 deny tcp any eq 137 any
access-list 121 deny tcp any eq 138 any
access-list 121 deny tcp any eq 139 any
access-list 121 permit ip any any time-range TIME
dialer-list 1 protocol ip permit
!
line con 0
exec-timeout 120 0
transport input none
stopbits 1
line vty 0 4
exec-timeout 0 0
login local
!
time-range TIME
periodic daily 0:00 to 23:59
!
end

Any help greatly appreciated!

 

[mtnwinds]

I fixed it. The config was fine. I needed to change the DNS on the external NIC.

 

[LoneGamer]

This is quite simple. At the end of any ACL list, there is an implicit "deny any". Anything you don't specifically allow is blocked. Chances are, the port number your company uses to recieve e-mail is blocked. I'm in a proxy situation sometimes, I can recieve but not send. It's either your ACLs or a firewall/proxy server.