I have a Linux machine with two network interfaces, and I'd like to get the IP address of the PPP interface w1g1 but it doesn't show up in ifconfig. There is a public IP on the PPP interface, but there is no internet connection, I'm trying to troubleshoot but I need to get the IP address of the interface and I can't.

ifconfig :

eth0      Link encap:Ethernet  HWaddr 00:30:48:8D:F0:2C
          inet addr:192.168.2.254  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::230:48ff:fe8d:f02c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:9970 errors:0 dropped:567 overruns:0 frame:0
          TX packets:4338 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          RX bytes:1441024 (1.3 MiB)  TX bytes:915814 (894.3 KiB)

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:675 errors:0 dropped:0 overruns:0 frame:0
          TX packets:675 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:50659 (49.4 KiB)  TX bytes:50659 (49.4 KiB)

w1g1      Link encap:Point-to-Point Protocol
          UP POINTOPOINT RUNNING NOARP  MTU:240  Metric:1
          RX packets:748994 errors:0 dropped:0 overruns:0 frame:0
          TX packets:748992 errors:0 dropped:0 overruns:0 carrier:3
          collisions:0 txqueuelen:100
          RX bytes:179758560 (171.4 MiB)  TX bytes:179758080 (171.4 MiB)
          Interrupt:177 Memory:f881c400-f881e3ff

w1g1 is connected to a modem by an RJ45<->Serial cable and the modem is connected to the phone line. The modem is a NOKIA DNT2Mi you can see it here

Routing table :

192.168.2.0/24 dev eth0  proto kernel  scope link  src 192.168.2.254
169.254.0.0/16 dev eth0  scope link
default via 192.168.2.180 dev eth0