Messages in this thread | | | Date | Sun, 7 Nov 1999 22:00:35 -0500 (EST) | From | "Mike A. Harris" <> | Subject | PPP devices given eth0 IP address upon connect. |
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Some time ago, I was trying to configure a dialup firewall with PPP, and was having some trouble with the IP address that ppp was getting. I strongly believe this to be a kernel bug, and so I would like some feedback from the appropriate people please.
The problem is that when the PPP interface came up, the dynamic IP address given from the ISP end was *NOT* the IP address that the PPP interface used but rather PPP was using the IP address of the ETHERNET interface!
This problem was and is replicable. It happens with 2.0.x, 2.2.x kernels. All testing that has taken place is using the proper required tools for the given kernel (ie: pppd version), and the 2.0 tests were on RedHat 5.2, while the 2.2 tests are on RedHat 6.0).
Here are the details of the problem:
The local ethernet card, is configured to 10.1.1.1/24. The entire network is configured using a CIDR netmask of 24 bits, and works perfectly.
When PPP is brought up using "ifup ppp0" from RedHat, the internet connection is established to the ISP, the debugging info shows the ISP's assigned IP address which is all proper. At this point, doing "ifconfig" shows that ppp0 is using the IP address for the ETHERNET interface, and NOT THE ONE GIVEN FROM THE ISP!
Here is the wild part: If I reconfigure this machine to use an IP address of 192.168.1.40/24, and put it on another LAN that uses that network instead - EVERYTHING works. No change to ppp configuration, and it works fine. It connects to the internet, gets an IP, and just simply works.
Change the IP address to 10.x.x.x, and reconfigure the box to use that IP range instead, and PPP takes over the IP address of the eth0 device upon connection.
I have done some research on this, and I have now found that other people are having the problem too. Someone else has found that using an IP address with a "0" in it appears to cause this too. The IP that they are using is 192.168.0.10.
This is a very strange problem indeed. I believe it is kernel related, and would like some help to try and track down the problem if possible. It could also be a possible bug in pppd I suppose, so any help with that would also be appreciated.
What could POSSIBLY cause a ppp interface to take over an ethernet interface's IP address upon connection and IP negotiation?
Any help greatly appreciated.
TTYL
-- Mike A. Harris Linux advocate Computer Consultant GNU advocate Capslock Consulting Open Source advocate
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