Home / server / Questions / 576192
Accepted
Itai Ganot
Asked: 2014-02-18 06:49:28 +0800 CST

Trying to understand the correct way to create a static route in CentOS, please assist

  • 772

I've been trying to understand what's the correct way to add a static route on a CentOS 6.x machine. In some forums they say to create a file named route-dev_name (for example route-eth0) with the relevant route and place it in /etc/sysconfig/network-scripts , in some forums they say the file should be named static-routes , in both cases I'm unable to set a static route. It seems like in some CentOS releases it works only when naming the file route-dev_name and in some it only works when naming the file static-routes.. Can anyone please assist me? This is the content of my route file:

192.168.20.0/24 via 192.168.20.253 dev eth0

Thanks in advance

linux

6 Answers

  1. Create a file in /etc/syconfig/network-scripts/route-eth0

    add add the following

    192.168.20.0/24 via 192.168.20.253 dev eth0

    I have always used this approach. I have found this to be the best approach.

    FYI: Check -- https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s1-networkscripts-static-routes.html

    • 8
  2. Best Answer

    RH style device dependent routes defined using /etc/sysconfig/network-scripts/route-device files has caused lots of problems.

    So real sysadmins use only /etc/sysconfig/static-routes file without device dependency:

    any net 10.0.0.0 netmask 255.255.255.0 gw 192.168.0.1

    Problems:

    • When physical devices are bonded, you need to remember to chance route-device file too
    • When you reorganize adapters in a virtual machine.

    Naturally one should always use bridge devices, so one could avoid route-device file problems.

    Also notice the syntax in /etc/sysconfig/static-routes file, sniplet from /etc/init.d/network:

        # Add non interface-specific static-routes.
    if [ -f /etc/sysconfig/static-routes ]; then
       if [ -x /sbin/route ]; then
           grep "^any" /etc/sysconfig/static-routes | while read ignore args ; do
               /sbin/route add -$args
           done
       else
           net_log $"Legacy static-route support not available: /sbin/route not found"
       fi
    fi
    • 8

  3. There is an easier way to add routes...

    This file - /etc/init.d/network - is launched when the PC is booting, and it uses a file /etc/sysconfig/static-routes to add static routes

    You have to create it because it doesn't exist.

    If you read carefully the file /etc/init.d/network, it reads in this file each line to add routes, those line must begin by "any", and "route add -" is already known.

    So in the file you are going to create >> /etc/sysconfig/static-routes, you have to write :

    any net 10.0.0.0 netmask 255.255.255.0 gw 192.168.0.1 eth0
    • where 10.0.0.0/24 is the network you want to reach (255.255.255.0 is the mask)
    • where gw 192.168.0.1 is the gateway to reach (certainly the router)
    • where eth0 is the interface where to use.

    This is the best way for adding static routes, 1 file for everything (not X files for X interfaces)

    • 5

  4. I always use the route-ethX file approach on my CentOS 6.4 and 6.5 :

    Create/edit file /etc/sysconfig/network-scripts/route-ethX (where X is your interface number) and set your route in this file :

    192.168.20.0/24 via 192.168.20.253 dev eth0

    You can also edit this file using the following format (personally i prefer the first syntax) :

    GATEWAY0=192.168.20.253
NETMASK0=255.255.255.0
ADDRESS0=192.168.20.0

    Then restart the network to apply the changes :

    service network restart

    Further reading : https://www.centos.org/docs/5/html/5.2/Deployment_Guide/s1-networkscripts-static-routes.html

    • 1

  5. In /etc/sysconfig/network-scripts there's a script ifup-routes. It looks for files with the name route-dev_name, e.g. route-eth0.

    • 0

  6. On my case the file "/etc/sysconfig/network-scripts/route-device" didnt exist.

    I proceed to add the required network or ip on the file "/etc/sysconfig/static-routes" and to make it permanently, I rebooted the machine and it turned out working as expected.

    it was done in a : cat /etc/centos-release CentOS Linux release 7.5.1804 (Core)

    Best regards,

    Manuel Lazo

    • 0