RedHat and DSL


We have encountered a problem for DSL customers running the RedHat distribution of Linux. This problem affects customers using RedHat Linux 6.0 or above.


The Problem:
Verion 6.x
The pump DHCP client included with RedHat 6.x is flawed. When you boot the computer, it will obtain an IP and lease from the DHCP server, as it should. However, in most cases, it will not release/renew the IP when the lease on the IP address expires.

Note: If you want to know what DHCP is, you can read about it at Whatis.com

Unfortunately, the DHCP server has no way of knowing that your system is still using the original IP address, so it will assign it to another DSL customer even though your computer is still using it.

This causes an IP conflict which results in one or both of the affected customers connections not working. RedHat's update for pump does not resolve the issue.

In order to prevent disrupting other users' service, the only reliable method of dealing with the problem caused by pump is to disable DSL service to the user running pump.


Version 7.x
This newer version has a similar problem, but only affects your ability to connect.

The newer version of RedHat's pump still has problems renewing IP addresses through DHCP. However once it fails, the new version of pump will lose the IP address it was assigned. This means that you will lose all Internet connectivity.

However, there are workarounds.
 

The Solutions

Solution 1:
Follow these steps to install this package and configure your system:

1. Login as root.

2. Go to the RedHat RPM search page. There, do a search for dhcpcd.

3. Download the latest dhcpcd DHCP client. (It should be named something long the lines of "dhcp-1.3.xxxxxxxx.rpm".)

4. Install it:

rpm -Uvh dhcpcd-1.3.xxxxxxxx.rpm

5. Click on the following link to download the file:

6. Unpack the file:

tar -zxvf ifscripts.tgz

7. Set the permissions on the files and copy them to /sbin:

chown root:root ifup
chown root:root ifdown
chmod 0755 ifup
chmod 0755 ifdown
mv /sbin/ifup /sbin/ifup.old ; cp ifup /sbin
mv /sbin/ifdown /sbin/ifdown.old ; cp ifdown /sbin

8. Reboot your computer:

shutdown -r now

Solution 2:
The other possible solution is to configure the Cisco 675 to use PPP mode instead of Bridged Ethernet. In PPP mode, the Cisco logs in (similar to a modem connection) and is assigned an IP address. Each computer hooked up to the Cisco will either get assigned an internal-only IP address (by the Cisco) or you can specify an internal-only IP address for each computer.

You can find instructions for reconfiguring the Cisco 675 for PPP at http://www.azstarnet.com/service/dsl/ppp/cisco675.html

Note: The instructions were written for Mac or Windows, but you can hook up the management cable and skip down to the step where you log in to the Cisco's OS.