How to Check Interface Status

After PPP is started, you can use ifconfig to monitor the current state of the line, using only the PPP interface name as an argument. Example 23-4 shows sample output from ifconfig for PPP links that are running.

If a user is privileged (root), and issues an ifconfig command, machine addresses are displayed in the output as shown in the following example.

1. Become superuser.

2. Type:

   ifconfig ipdptp0

Example 23-4 ifconfig Output for Point-to-Point Link

nomadb# ifconfig ipdptp0

ipdptp0: flags=28d1<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST,UNNUMBERED> mtu 1500
        inet 129.144.111.26 --> 129.144.116.157 netmask ffff0000
        ether 0:0:0:0:0:0 

You receive output similar to that in Example 23-5 for both standard and dynamic point-to-point links.

Example 23-5 ifconfig Output for Multipoint Link

nubian# ifconfig ipd0

ipd0: flags=c1<UP,RUNNING,NOARP> mtu 1500
        inet 129.144.201.191 netmask ffffff00
        ether 0:0:0:0:0:0

If ifconfig does not display UP and RUNNING, you did not configure PPP correctly. For more information on ifconfig, see "ifconfig Command" and the ifconfig(1M) man page.