This article is very good, multi-Nic recommended with a fourth method.
Http://blog.sina.com.cn/s/blog_828e50020101ern5.html
Add a permanent static route to CentOS
A static route is required when using a dual NIC with 2 gateways at the same time. Of course, there are many times when you need to add routes.
Operating system version centos-6.4 64bit
One: Use the route command to add
1, the route command added by using the route, the machine restarts or the network card restarts after the route is invalid, method:
Routes added to the host
# route Add–host 192.168.1.11 Dev eth0
# route Add–host 192.168.1.12 GW 192.168.1.1
Routes added to the network
# route add–net 192.168.1.11 netmask 255.255.255.0 Dev eth0
# route add–net 192.168.1.11 netmask 255.255.255.0 GW 192.168.1.1
# route add–net 192.168.1.0/24 Dev eth1
Add a default gateway
# route add default GW 192.168.2.1
Delete route
# route Del–host 192.168.1.11 Dev eth0
2. You can also use IP commands to add and remove routes
IP route add default via 172.16.10.2 dev eth0
IP route add 172.16.1.0/24 via 172.16.10.2 Dev eth0
The format is as follows:
IP route
Default via Gateway Dev interface
Ip/netmask via Gateway Dev interface
Two: The method of setting the permanent route under Linux:
1. Add in/etc/rc.local
Method:
Route add-net 192.168.3.0/24 Dev eth0
Route add-net 192.168.2.0/24 GW 192.168.2.254
2. Add to end in/etc/sysconfig/network
Method:
Gateway=gw-ip
Or
Gateway=gw-dev
3./etc/sysconfig/static-routes:
Any net 192.168.3.0/24 GW 192.168.3.254
Any net 10.250.228.128 netmask 255.255.255.192 GW 10.250.228.129
If adding a route in Rc.local causes NFS to not mount the problem automatically, it is best to use the Static-routes method. Both the restart system and the service network restart will take effect.
To resolve the NFS problem description:
In the order of Linux boot, Rc.local inside the content is in Linux all services are started, and finally executed, that is, the contents of this is executed after Netfs, that is to say, when the Netfs startup, the static route on the server is not added, so netfs mount can not be successful.
4, add the route under/etc/sysconfig/network-script/route-interface (one file per interface, if not, create one, you can only add routes for that interface)
The format is as follows:
Network/prefix via Gateway Dev intf
For example, add a default gateway to eth0:
Vim/etc/sysconfig/network-scripts/route-eth0
#添加如下内容 (can omit dev eth0)
0.0.0.0/0 via 172.16.10.2 Dev eth0
PS: Note that the mask here is 0 instead of 32, because this is a network segment rather than a route.
After saving exits, service network restart.
Use Route-n or netstat-r to view the routing table.
[Root@localhost ~]# Route-n
Kernel IP Routing Table
Destination Gateway genmask Flags Metric Ref use Iface
172.16.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0
0.0.0.0 172.16.10.2 0.0.0.0 UG 0 0 0 eth0
The default route has been added to the routing table.
Note If you have two network cards, you need to set a default route to access the Internet.
All methods for adding static routes are validated on the centos6.4 and are correct.