Posting this as a solution since I didn't see the exact question when I Googled and a lot of what is written is fairly esoteric and not really germane:

I'd created an ifcfg-eth1:1 on a RHEL5.3 server. On running "ifup eth1:1" I got the following error.
"RTNETLINK answers: File exists"
A Google search mentioned this various times but nothing truly consistent and nothing directly related to what I was doing. Some mentioned routing which made me look at "netstat -rn" outuput. I saw it had added a new bogus route to the table. Also there was some discussion of the fact that message is somewhat bogus as it isn't a regular "file" that exists but rather a "file" in the broad sense that sockets, shared memory segment, et al are considered "files".

One link mentioned /usr/share/doc/initscripts<version> directory.
Reviewing documents there led me to the realization that starting any alias for an interface will attempt to also invoke the routing created for that interface. (We have a route-eth1 file for this due to the fact that default gateway is on eth0 which is the external facing NIC.)
Further read indicated there is an option for alias files to start the alias interface at same time as primary or not. The default is to start at same time.

All this along with the bogus route led me to the conclusion the "file" that "exists" is the route added at start of eth1.

Resolution was simply to "ifdown eth1:1; ifdown eth1; ifup eth1". The ifup eth1 at end starts both the primary and the alias AND only sets the route once so I didn't see the error starting this way.

Thanks for taking the time to write this up & post it. Let's hope it does indeed help someone else.

Thanks, this was exactly what I was looking for. Now if only all my questions were pre-answered like this!

thanks!

Very useful, your post pointed me at the right thing straight away.
For my setup eth1 is a secondary interface on the local LAN, 10.0.0.4, given that eth0 is the external interface the default gateway set in /etc/sysconfig/network points out that way..
I had added a line into route-eth1 defining a static route for the same LAN as eth1 is already in as I am getting the odd issue with a vpn session in not getting traffic back, despite getting assigned an IP in the same range. But after adding the route i was getting the "RTNETLINK answers: File exists". No route had been added showing the gateway 10.1.0.254 so i removed the line/route and hey presto, no error message.

Thanks again.
mark

Thanks to those who took the time to give rep for the post. Too bad the 1st post in a thread is presumed to be a question & can't be marked "Helpful".

You can always click the little scales under MensaWater's name to give him Rep for the post ;-)

Indeed, at least 3 people did just that. My point is that each could have given a well deserved extra point through the "helpful" system if it were available.

Well you learn something every day! That's what I did, and thanks for that tip too

wrt the error, I got the error on a CentOS box where I bonded a couple of NICs. The error was on bond0 when I did a:

What got me is that I've done this dozens of times and this was the only time I received the error - everything looked fine (ifconfig) and everything worked.

So then, I restarted the network again and no error. All was well in syslog too, so I still don't know what caused the error, but at least I know why it might occur if it happens again, and what I might do to alleviate the error.

Kindest regards,