the NIC could not communicate normally, use command 'netstate -rn' had this output:
0.0.0.0 0.0.0.0 0.0.0.0 U 0 0 0 bond0
use route -delete command to delete the route, but it's configured again automatically.
1. check the file '/etc/sysconfig/network/routes' , but it didn't contain the route
10.0.40.103 10.80.152.254 255.255.255.255 bond1
default 10.80.152.1 - - S
2. check bond0 and the NIC bonded in bond0, whether they have the route configuration. they don't have the config either.
3. use command 'crontab -l' to review all cron task, whether is there any task to configure the route, but not found.
4. check the user profile './bashrc, /etc/profile'
cat /etc/profile, found one sentence 'route add 0.0.0.0 mask 0.0.0.0 .0.0.0.0' wrote on the bottom of the file. so we were sure the sentence can generate the route when load user profile.
delete the sentence and save the profile file, then delete the route. the NIC can run normally, and the 0.0.0.0 route didn't appear again.
1. the route wrote in the file '/etc/sysconfig/network/routes'
2. configured in bond0 or the NIC bonded in bond0
3. use command 'crontab -l' to review all cron task, whether is there any task to configure the route.
4. wrote in user environment file, such as './bashrc, /etc/profile'
/etc/profile is very important, do not modify it freely.