Configuring a Cisco Router using Access Lists for use with LapLink - Search Again

SUMMARY

I'm concerned about using LapLink on my corporate network, and want to understand LapLink's Security features. Also, I'm also looking for information about how I can configure my Cisco Router to allow LapLink to make secure connections. Can you help me?

SOLUTION

Currently there is no proxy or stateful inspection mechanism for LapLink. Access is allowed by opening TCP port 1547 to specific hosts or the network at the discretion of the security administrator. For sites using NAT with private address space or NAT with port multiplexing, you will be unable to allow incoming LapLink connections. Sites using NAT and mapping their internal IP addresses to valid public addresses can, if they choose, set up static mappings for particular LapLink hosts to be reached from the outside.

For demonstration purposes we will be referencing the private network 192.168.100.0/24 as our internal trusted network with all filtering relative to the public Internet. Implementation is similar for any external network.

For this example we show how to permit LapLink to connect to the host 192.168.100.45; permitting LapLink to connect to multiple hosts or an entire network is a trivial modification. This does not imply that hosts with private addresses can actually be reached from outside the trusted network, but is a safe example to use.

In privileged exec mode, create the following access-list (or append to an existing access-list) then apply the access-group to the external interface.

1. access-list 110 permit tcp any 192.168.100.45 eq 1547


2. interface ethernet0


3. ip address 192.168.100.1

1. access-group 110 in

Related Articles

Configuring a 'CheckPoint Firewall-1' for use with LapLink    Configuring a 3Com Home Connect Wireless Gateway for LapLink    Configuring a Cisco PIX Firewall for use with LapLink    Configuring a Linksys Broadband Etherfast Cable/DSL Router for use with LapLink    Configuring a NetGear Cable/DSL Router for use with LapLink    Configuring a Network Associates Gauntlet Firewall for use with LapLink

Last updated: Friday, August 10, 2001

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