Configuring USB Modem Dial-up Connection. [Solved]

[raja_s_patil]

I am trying to install and configure USB modem and a dialup connection
for onsite use for my Dell-Vostro-1710 laptop with Kubuntu 8.04.1
In office I am using Broadband connection by pointing eth0 to
Broadband Router at 192.168.1.1. I would like to reserve settings
for Router as well whenever needed I should be able to use USB modem
when I am on Client sites where no internet facility is available or
to make internet available when I am Travelling. Output of various commands
is as follows.

rsp@rsp-1710:~$ wvdial
--> WvDial: Internet dialer version 1.60
--> Cannot get information for serial port.
--> Initializing modem.
--> Sending: ATZ
ATZ
OK
--> Sending: ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
OK
--> Modem initialized.
--> Sending: ATDT#777
--> Waiting for carrier.
ATDT#777
CONNECT
--> Carrier detected. Starting PPP immediately.
--> Starting pppd at Fri Mar 6 14:03:22 2009
--> Warning: Could not modify /etc/ppp/pap-secrets: Permission denied
--> --> PAP (Password Authentication Protocol) may be flaky.
--> Warning: Could not modify /etc/ppp/chap-secrets: Permission denied
--> --> CHAP (Challenge Handshake) may be flaky.
--> Pid of pppd: 9926
--> Using interface ppp0
--> pppd: ȧ[06][08]`¥[06][08]
--> pppd: ȧ[06][08]`¥[06][08]
--> pppd: ȧ[06][08]`¥[06][08]
--> pppd: ȧ[06][08]`¥[06][08]
--> pppd: ȧ[06][08]`¥[06][08]
--> pppd: ȧ[06][08]`¥[06][08]
--> local IP address 59.161.63.249
--> pppd: ȧ[06][08]`¥[06][08]
--> remote IP address 172.23.119.14
--> pppd: ȧ[06][08]`¥[06][08]
--> primary DNS address 202.54.29.5
--> pppd: ȧ[06][08]`¥[06][08]
--> secondary DNS address 202.54.10.2
--> pppd: ȧ[06][08]`¥[06][08]

rsp@rsp-1710:~$ ifconfig
eth0 Link encap:Ethernet HWaddr 00:21:70:c7:c7:35
inet addr:192.168.1.248 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::221:70ff:fec7:c735/64 Scope:Link
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:429 errors:0 dropped:2033352149 overruns:0 frame:0
TX packets:308 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:271102 (264.7 KB) TX bytes:38048 (37.1 KB)
Interrupt:218 Base address:0xe000

ppp0 Link encap:Point-to-Point Protocol
inet addr:59.161.63.249 P-t-P:172.23.119.14 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1400 Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:5 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:64 (64.0 B) TX bytes:97 (97.0 B)

rsp@rsp-1710:~$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.23.119.14 * 255.255.255.255 UH 0 0 0 ppp0
172.16.183.0 * 255.255.255.0 U 0 0 0 vmnet8
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
10.1.1.0 * 255.255.255.0 U 0 0 0 vmnet1
link-local * 255.255.0.0 U 1000 0 0 eth0
default 192.168.1.1 0.0.0.0 UG 100 0 0 eth0

rsp@rsp-1710:~$ ping 218.248.255.145
PING 218.248.255.145 (218.248.255.145) 56(84) bytes of data.
From 192.168.1.248 icmp_seq=1 Destination Host Unreachable
From 192.168.1.248 icmp_seq=2 Destination Host Unreachable
From 192.168.1.248 icmp_seq=3 Destination Host Unreachable

from above its clear that Connection is established but proper route is not
set and ping commnd is going vial default route of eth0

How can I change this so that when eth0 is not connected ppp0 should be used
for routing

Thanks and best regards

[raja_s_patil]

Re: Configuring USB Modem Dial-up Connection. [Solved]

man pppd gave the solution.

just add replacedefaultroute to /etc/ppp/options file.

Now everything is fine as soon as wvdial finishes the route command
shows default route to ppp0 and back to eth0 when wvdial is terminated.
exactly what i wanted.

BTW every time i have to turn the firewall off to access internet via ppp0
i need to modify the fw config

Thanks and best regards