Configuring a Cisco 827 / 1700 / 2600 / 3600 Router for use with LapLink
SUMMARY
I have a Cisco router. How can I configure it to allow LapLink connections from the Internet?
SOLUTION
You must configure the router to forward TCP port 1547 to the private IP address of the Laplink host computer. Cisco brand routers run IOS Software and use a command line interface for configuration of the IOS.
NOTE 1: The steps in this article are specific to establishing a connection on port 1547. It is possible to change the port that Laplink Gold uses to connect. This will allow you to have multiple computers behind the same router. See Technical Document 618: Changing the Firewall or Router Port used by LapLink Gold for more information on how to change the port. Use the same steps here to setup a configuration for a different port number to a different Host computer.
NOTE 2: The purpose of this document is to provide the user with the required commands used to forward TCP port 1547 to the LapLink host computer. This document assumes that the user is familiar with IOS configuration fundamentals. Laplink technicians cannot provide general assistance with Cisco IOS commands.
Forwarding Port 1547:
Port forwarding is achieved through a static NAT translation using the optional extendable keyword. The following is the syntax for the IOS command that will automatically redirect all LapLink traffic to a LapLink host computer.
ip nat inside source static tcp [internal address of LapLink computer] 1547 [public address assigned by ISP] 1547 extendable
This command is entered while in global configuration mode. This assumes you have already defined a NAT inside and outside interface using the ip nat inside and ip nat outside commands while in interface configuration mode for the respective interface.
For the purpose of illustration, what follows is a sample IOS configuration that incorporates the above command to forward TCP port 1547 to the LapLink host computer. This example is for a Cisco 827 router that contains an ADSL Wan Interface Card. It would also work for Cisco 1417, SOHO77, and 1700/2600/3600 routers.
Current Configuration:
!
version 12.1
service timestamps debug uptime
service timestamps log uptime
!
hostname cisco827
!
ip subnet-zero
no ip domain-lookup
!
bridge irb
!
interface Ethernet0
ip address 192.168.0.1 255.255.255.0
ip nat inside
!
!--- This is the private local IP address of the inside interface of
!--- the router.
!
interface ATM0
no ip address
no atm ilmi-keepalive
pvc 0/35
encapsulation aal5snap
!
bundle-enable
dsl operating-mode auto
bridge-group 1
!
interface BVI1
ip address 171.68.1.1 255.255.255.240
ip nat outside
!
!--- This is the global public IP address of the outside interface of
!--- the router. This is provided to you by your ISP.
!
ip nat inside source static tcp 192.168.0.4 1547 171.68.1.1 1547 extendable
!
!--- This statement performs the static address translation for the
!--- LapLink host computer. With this statement, users trying to reach
!--- 171.68.1.1 port 1547 (LapLink) will be automatically redirected to
!--- 192.168.0.4 port 1547 (LapLink), which in this case is the host
!--- computer running LapLink.
!
ip classless
ip route 0.0.0.0 0.0.0.0 171.68.1.254
!
bridge 1 protocol ieee
bridge 1 route ip
!
end
If you need additional information or support, please contact Cisco Technical Assistance Center.
Connecting to a Laplink host computer behind the Cisco router:
Once the port forwarding has been accomplished, you are ready to connect in Laplink from a different location. Please see Technical Document # 201: Using ILS to Connect over the Internet with LapLink.
-Or- Technical Document # 203: Using IP Addresses to Manually Connect over the Internet with LapLink.
This Article can be found by searching for:
Products: LapLink Gold 11.5, LapLink Classic, LapLink Gold 11.x, LapLink Technical, LapLink Professional, LapLink Gold, LapLink NT, LapLink 2000
Platforms: WinXP, WinMe, Win98/SE, WinNT, Win2K, Win95
Keywords: Security: Firewall, Security: Internet, Connections: Internet, Network: Router, Network: TCP/IP, Internet: Firewalls, Internet: Router, Internet: NAT
Last updated: Friday, September 05, 2008
Article #45
Legacy Article #2025