Red Hat Bugzilla – Bug 17879
linuxconf + RH scripts create Class A routing error
Last modified: 2008-05-01 11:37:58 EDT
On a machine on a DSL line on an 64.* subnet with a mask of 255.255.255.248, set up through linuxconf, a spurious line shows up in the routing table that disables any attempt to connect to any outside site in the 64.*.*.* Class A: 64.0.0.0 * 255.0.0.0 U 0 0 0 eth0 If I do an 'ifconfig etho down' and then 'ifconfig eth0 up' that line returns! Please, where do I disable this 'feature'! This is not anything I've entered anywhere, but some artifact of linuxconf + Redhat's scripts. Nor does 'route del 64.0.0.0' work to clear this bad entry. I guess some script is confused, but not sure where the error lives. BTW, it would be nice if RH produced a guide to doing configuration _without_ problematic utilities like linuxconf - step by step guides to doing configuration by hand, and to disabling scripts when they disable good operations.
Check that NETMASK is defined right in /etc/sysconfig/network-scripts/ifcfg-eth0. NETWORK need not be defined, but if it is, check it too.
I was wrong on where the errror was coming in. I am using IP aliasing on this system (configured by hand through rc.local, following the formula in the HOWTO and a Sys Admin article), and it turns out that ifconfig was (1) assigning the wrong netmask to the aliased IP's and (2) adding the 64.0.0.0 line as some sort of byproduct of that mistake, having apparently deduced that I had a Class A. Explicitly setting the netmask for the aliased IPs fixed it. On a similar system with a 255.255.255.0 netmask ifconfig properly used the mask for the primary port for the aliased IPs too, but on this one with 255.255.255.248 for the mask it gave the aliased IPs a 255.0.0.0 netmask. I guess when ifconfig was written the authors could conceive of owning a whole Class A, but not of subnetting below a Class C. Sorry for my confusion. Thanks for the response.
Okay. I guess I'll close this bug report then....