Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

First time user of a Cisco (871W) router. Some questions

Hi all,

I have a Cisco 871W, but no experience .. :)

My connection is 100/100 Mbit. And I have four PC's connected to the router. One in every connection. But now every PC gets about 25/25 Mbit. The router seems to split the speed. Even if only one PC are on. How can I fix this?

Next question is about portforwarding. What is the command to make the ports 1300-1400 go to the server with IP ? What do I have to do?

I'll be very happy if any of you can help me!


Re: First time user of a Cisco (871W) router. Some questions

How are you checking that the speed is 25/25 Mbit? 100Mbps is the speed of the interface and the throughput will depend on your Internet connectivity. You will need to configure the application to use server at for ports 1300-1400.

New Member

Re: First time user of a Cisco (871W) router. Some questions

Hello Andy,

The default Fast Ethernet switch ports for the 871 routers is set to auto-duplex and auto-speed. The switch ports only work in 10/100 half and full duplex, so I am not sure how you are getting 25Mbits.

There are two IOS commands to verify Ethernet port function. Be sure to be in the ENABLED mode of the router.

This command will give you the summary of all the switch ports:

Router#sh interface status

Notice under the column Duplex and Speed Type, the router will indicate the interfaces as a-full and a-100. This means Auto Duplex is at Full and Auto-Speed is at 100.

To get greater detail, use the following command for each Ethernet interface.

Router#sh interface fa0

About 8 lines down you will see the line that states FA0 is set to full duplex and 100Mbits line speed:

Full-duplex, 100Mb/s, 100BaseTX/FX

Hope this helps.


New Member

Re: First time user of a Cisco (871W) router. Some questions

For the port forwarding and using a range of port numbers, the IOS does not make it easy.

There are two ways to accomplish this - one is to define the TCP/UDP port number individually or the second, define the NAT pool and access list to specify the range.

The first is straightforward, but requires alot of lines. In your case, a line for each port number from 1300 to 1400. Must be in Config mode.

Here is the command:

Router# config t

Router(config)#ip nat inside source static tcp 1300 interface fa4 1300

Router(config)# exit (after you have inputted the 100 lines)

The second method is explained in this article.

Hope this helps.


CreatePlease to create content