Routing Interview Question:

What is ifconfig?

Submitted by: Administrator

It is always best to start investigating routing problems by making sure that your interfaces are set up correctly. By running ifconfig, you can see your current interface setup: # ifconfig -a lo0: flags=849<UP,LOOPBACK,RUNNING,MULTICAST> mtu 8232 inet 127.0.0.1 netmask ff000000 le0: flags=863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST> mtu 1500 inet 150.101.16.28 netmask ffffff00 broadcast 150.101.16.255 ether 8:0:20:10:78:d When an interface is brought up, it automatically creates a route. This route will be to the local network for multipoint interfaces (ether, FDDI, TR, etc), or to a host for point-to-point interfaces (PPP). If your main interface (le0 in the above example) is not UP and RUNNING, clearly no routing will be occurring through it. If the interface is UP, you will also want to examine the inet and netmask entries of your main interface, and make sure they are set correctly. If the inet is set wrong, check your /etc/hostname.interfacename file (ie, hostname.le0) and your /etc/hosts file. If the netmask is set wrong, check your /etc/netmasks file
Submitted by: Administrator