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Community Member

Cisco 876 integrated services router and SBS2003

Please help as I am tearing my hair out trying to get this working and have little experience with Router setups.

I have installed an SBS2003 server with 2 NIC's and am trying to install a CISCO 876 router to control the internet access.

Here is the network to be defined :-

Fixed IP provided by ISP

Router external interface as FIXED IP

VLAN1 defined as, with DHCP

External NIC of SBS2003

Internal NIC of SBS2003

Workstations have 192.168.1.x addresses, or 10.10.10.x addresses.

Here is what I want to achieve :-

Most user devices will sit off the 192.168.1.x network range. The range will be used for network cameras etc. The SBS2003 server is an EXCHANGE email server, DNS server and provides DHCP for workstations on the 192.168.1.x network.

The address needs to recieve all SMTP mail (port 25)

Also I want 443, 444, and VPN ports routed to SBS2003 server.

Address is a Blackberry server and so has to receive messages for port 3101 both TCP and UDP.

All 192.168.1.x and 10.10.10.x addresses should be able to reach internet.

Please let me know what fixed and dynamic routes I should set up in router, should I use RIP and where NAT should be translating to in the router to send the smtp email messages and other things to SBS2003 server. (Should it be the external address or the server address ? )

(I have set it up for both but never get any messages into the mail server when testing it :-) - I have had to back out changes now so the network is not live, I have gone back to an ADSL modem only )

Thanks in advance

Ian Murdoch


Re: Cisco 876 integrated services router and SBS2003


If I have understood your setup it would be something like this:

ip nat inside source static (public)

ip nat inside source static

ip nat inside source list 7 int e 1 overload

interface e 0

ip address

ip nat inside

interface e 1

ip address

ip nat outside

ip route (public gateway)

access-list 7 permit

access-list 7 permit

HTH, tell if it does not :)



Community Member

Re: Cisco 876 integrated services router and SBS2003


Thanks for the fast response.

Can I assume that in this example is the fixed IP from the ISP, if so what are and (DNS servers or something else ?)

Would I need to do any Nat for the specific ports or would this not be necessary.



Re: Cisco 876 integrated services router and SBS2003

Hi again, is your default gateway (your IPS's router)

Since i've set up static nat it will work for all ports for each ip. ( an .11)

Second, is your wan IP (public)

towards your ISP. You need to set up dns to your ISP dns server. (in your dhcp scope)

If you want a scope for 192.168.1.X

you need to create another vlan for that subnet and dhcp on the router. is used as example. its actually private addresses.




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