Installing USB modem ZTE AC2726 in Ubuntu 9.04 Jaunty

Recently i successfully installed ZTE AC-2726 modem that came with reliance wireless broadband connection. Below are the steps:

Insert the modem in USB interface and see if that gets detected.

$ lsusb
Bus 005 Device 002: ID 19d2:fff5

I noticed in /var/log/messsages that the device is detected as usb storage. To make it detected as modem we will use usb-modeswitch package. It is a Switching tool for controlling "flip flop" USB devices.

Download usb_switch package from here and install.
$ sudo dpkg -i usb-modeswitch_1.0.2-1_i386.deb

Unplug and plugin the modem back.

$ lsusb
Bus 005 Device 004: ID 19d2:fff1 <- Notice the change in product id

$ sudo modprobe usbserial vendor=0x19d2 product=0xfff1

You can see in the logs that the modem is detected correctly now. To detect & configure the dialer config run:

$ sudo wvdialconf

Check and add the missing entries in wvdial conf as found below:
$ sudo vi /etc/wvdial.conf
Phone = #777
Password = <Your Password>
Username = <Your Login Name>
Baud = 460800
Stupid Mode = 1
New PPPD = 1
Tonline = 0

Note: Give a valid username & password in the corresponding lines above and uncomment them (Hint: remove  ";" from the beginning of the line).

$ sudo wvdial

The connection started working. Note that you can also configure gnome-ppp or kpp to connect.

Asterisk Updates

In my asterisk server i installed all updates available from the repos. After rebooting the server, all my iax2 extensions stopped working.

I also found that there is one more interface virbr0 up with ip address 192.168.122.1. I stopped dnsmasq service which was listening on this ip. Then disabled dnsmasq (chkconfig dnsmasq off). Rebooted the box. Still the interface was present.

Since there is no use of this service in my server i removed dnsmaq along with all the dependencies. Did this:
# rpm -e dnsmasq libvirt-0.3.3-14.el5_3.1.i386 NetworkManager-0.7.0-4.el5_3.i386 NetworkManager-glib-0.7.0-4.el5_3.i386 libvirt-python-0.3.3-14.el5_3.1.i386

The Virtual Interface went away but still iax2 extensions were not working. Then, found the following error in /var/log/asterisk/full
ERROR[2659] chan_iax2.c: Call rejected, CallToken Support required. If unexpected, resolve by placing address x.x.x.x in the calltokenignore list or setting user yyyy requirecalltoken=no

This is due to the security enhancement done in asterisk recently. IAX2 is now secured by call tokens which my iax2 doesn't support still. So i went ahead disabling this feature for now:

vi /etc/asterisk/iax.conf
Added calltokenoptional = 0.0.0.0/0.0.0.0 to the end. Then did: /usr/sbin/amportal restart

All iax2 extensions started working again. May be i should start looking for upgrading my clients to support call tokens for improved security.

References:
http://www.venturevoip.com/allnews.php?count=99999
http://downloads.asterisk.org/pub/security/AST-2009-006.html
Details are available in this pdf: http://svn.digium.com/svn/asterisk/branches/1.4/doc/IAX2-security.pdf