How if a machine can not ping outside

Default route error

1. check if can ping the gateway. Firstly, 192.168.0.1, and if double ips, 166.111.134.1

2. check the route: netstat -rn or route

3. you need set DEFROUTE='no' for NICs that are not the default route, here in the cslt case, 166.111.xx.xx.

4. The problem of #3 happs when grid-1 can not reach outside, and so cvss and bugdb can not send mails.

DNS resolution error

In centos7, DNS resolution never uses /etc/resolv.conf, but in sysconfig/nework-script/ifcfg-xxx, setting DNS1, DNS2, ..., etc. The default DNS, 192.168.0.50 may sometimes can not provide good dns response, so you can add additional DNS server:

• 166.111.8.28
• 166.111.8.29
• 114.114.114.114
• 8.8.8.8