Posts Tagged ‘adsl modem’

How to configure VIVACOM 3g USB ( internet ) modem HUAWEI Mobile broadband E173 on Debian and Ubuntu GNU / Linux

Wednesday, July 4th, 2012

Reading Time: 5minutes

sakis3g-configure-usb-modem-kdialog-shot

I've been given a HUAWEI Mobile Broadband E173 USB 3g model. The USB modem contains a flash USB Storage segment storing a little install program dedicated to make the modem work fine on Microsoft Windows XP / Vista / 7 and probably other M$ OSes. I'm a long time DebianGNU / Linux user and as a free software enthusiast I ofcourse wanted to be able to use Vivacom's 3G USB Modem on my Linux powered notebook.

Thanksfully as I've red on Vivacom's website the modem supports Linux OS 🙂

For those unaware in Bulgaria there are currently 3 major GSM network providers providing 3G internet this are;;;
 

  • VIVACOM – The ex Government ran national company BTC (Bulgarian Telecommunication Company)
  • M-Tel – The first GSM network provider that entered Bulgaria around year 1995
  • GLOBUL – The 3rd and last GSM mobile and net provider entered last and not so much used by Bulgarians today

Until today I had no experience in running any 3G modems on Linux, neither I had used the 3 networks 3G internet to determine which one is best, however I've been given for temporal use a VIVACOM 3G internet modem today so I proceeded to try installing it on my Debian host.

My Linux system is a bit strangely configured as I use wicd network connection manager -( wicd-gtk ) to manage wireless and LAN connections instead of the standard installed GNOME network manager – available through package ( network-manager-gnome ).

The reason I use wicd is not that it is so much better than GNOME network manger but rather for historical reasons because few years past I had impression it works better in connecting me to wireless networks. Another reason why I choosed wicd back then was the nice looking stats …

I tried plugging in the Vivacom USB 3G modem stick and checked in wicd to see if I can see a possibility to connect to the mobile opeartor 3G network but unfortunately nothing appeared.

Though the 3G adsl modem was unavailable straing in wicd, checking about it in the list of attached USB devices I could see it detected, e.g.:

noah:~# lsusb |grep -i huawei
Bus 001 Device 007: ID 12d1:1c05 Huawei Technologies Co., Ltd.

This was at least a good sign pointing me to the thoughts that the modem is probably gonna work.

I did a quick Google search to see if other people succeded running the device on a Linux host and came across a few blog posts in Bulgarian explaining a "success story" on Ubuntu Linux through using a tweakened shell script – sakis3g. For more on how the script works and script download check out Sakis3g

Here is a quote from sakis3g's website describing the script:
 

It automagically setups your USB or Bluetooth™ modem, and may even detect operator settings.
You should try it when anything else fails!

Sakis3g has different versions designed for for plenty of spacific hware architectures i.e. for (i386, amd64, armv4t, armv5t).
There is also a version of the script which by the way contains a combination of bash shell scripting instruction and some binary exec data.

To run sakis3g on my laptop I did:

1. Download sakis3g

My notebook architecture is 64 bit so I download and used the amd64 version of the script;;;

hipo@noah:~$ mkdir sakis3g
hipo@noah:~$ cd sakis3g
hipo@noah:~/sakis3g$ wget http://www.sakis3g.org/versions/latest/amd64/sakis3g.gz

I've made also a mirror of sakis3g i386, 64 bit and all architecture the mirrors just in case it disappears in future. The mirror versions of sakis3g are here:

a. sakis3g i386b. sakis3g amd64c. sakis3g all architectures source

2. Unarchive and make it executable

After downloading it as it is in gzip I had to do the usual de-gzipping and making the file executable;;;

hipo@noah:~/sakis3g$ /bin/gzip -d sakis3g.gz
hipo@noah:~/sakis3g$ chmod +x sakis3g

The script is then ready to run by either clicking twice on it or (as I prefer for debugging reasons to run it in terminal):

hipo@noah:~$ ./sakis3g

Something that I have wondered a bit was the dialog where I had to fill in some data of some variable APN abbreviation for – (Access Point Name)

The APN host for VIVACOM mobile internet is;;;
APN: internet.vivacom.bg

I've used the Windows configuration progrma to gather also the following data that I thought might be important for configuring the 3G adsl modem on the Linux host;;;

Auth: *99#
User: VIVACOM
pass: VIVACOM

Here are all the configuration screenshots I've taken from sakis3g and all the data that I filled in.
Next the following tiny window appeared on screen:

Sakis3g configure usb modem kdialog shot 1VIVACOM USB Modem Sakis 3g Shot 2sakis 3g usb modem vivacom connect screenshot 2vivacom 3g modem linux sakis3g enter pin dialog shot 4Sending pin screenshot 5 sakis3gAPN Dialog sakis3g screenshot 6sakis3g Internet Linux VIVACOM screenshot 7sakis3g Debian GNU Linux VIVACOM 3g Internet screenshot 8sakis3g initializing modem screenshot 9sakis3g successful connect to VIVACOM mobile 3g usb adls modem shot 10

Well that's all folks, now sakis3g succesfully connected to the I_net via an (PPP) VPN connection tunnel here is data from ifconfig command showing the succesful 3G connection to VIVACOM;;;

noah:~# /sbin/ifconfig ppp0
ppp0 Link encap:Point-to-Point Protocol
inet addr:10.58.146.232 P-t-P:10.64.64.64 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1
RX packets:2066 errors:1 dropped:0 overruns:0 frame:0
TX packets:1609 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:2232058 (2.1 MiB) TX bytes:341693 (333.6 KiB)

The internet via the 3G connection is not blazing fast but good enough to check your mail or read some webpages. VIVACOM currently has different (traffic limited packages) for their 3G internet, I'm not sure which package exactly is the 3G USB stick modem but probably the "quick" internet connection that is now would slow down once the traffic limit is reached …
Hope this post helps someone to configure 3G internet on VIVACOM in Debian and Ubuntu Linux. Though I've tested sakis3g on Debian it should work with no hassles on any other GNU Linux distribution that has bash installed.

Set ISP provider default DNS to overwrite DHCP settings on Debian / Ubuntu Linux

Monday, February 11th, 2013

Reading Time: 4minutes

dhcp linux ovewrite dns settings from console and terminal Debian Ubuntu Fedora CentOS Linux
 

These days, almost every home wireless ISP network router, ADSL modem etc. has its own local running DNS service. Generally this is very good as it puts off the burden of  Internet Service Provider DNS servers and "saves" multitude of users from so common overloads with ISP DNS Servers – caused by ISP DNS Service unable to handle the incoming user DNS (Domain resolve) traffic. Common scenario, where ISP DNS servers is unable to handle DNS traffic is when few thousands of users belonging to ISP gets infected with a Worm, Trojan horse or Virus doing plenty of DNS Spoofs and distributed DDoS attacks.

Though local DNS service (daemons) on local Cable and Wireless Network Routers is something designed to be good it becomes another bottleneck for DNS resolve problems, Calling the ISP tech support for help is often loose of time, as  in ISPs it is so rare to find someone understanding Linux Networking.

The periodic issues with DNS resolving from home routers in my observations has 3 main reasons;

  • Local Cheap network Wireless routers with slow hardware (CPU) and little memory are unable to handle DNS requests, because of torrent Downloads
     
  • DNS Wireless Router can't handle DNS requests to its DNS local service, because a small local network of computers with a landline and wireless (lets say 5 to 10) is trying to access the Internet (browsing) – again due to its low hardware paremeters router CPU heats up cause of multitude of DNS requests

     

  • Something is wrong with general network topology of PCs behind the router. Often people buy a router and use it shared with their neighbors – tampering with Router settings messing it up.

DNS resolving problems are even harder to track whether Internet provider has policy to deliver Internet via automated IP assignment protocol (DHCP),

A very common scenario, I've seen is Internet coming via ISP ADSL / Network router installed at home and mis-configured due to a custom user installation,   or because of ISP technician who installed router in hurry or lacked good competency and messed up with Router Network configuration.

During the years I had to install various Linux distributions for Desktop use in networks located behind such mis-configured Network Hubs. Because of this mis-configured DNS, even though Linux hosts succesfully graps the IP addresses for host IP, Gateway and DNS, they occasionally create problems with Internet Connection leaving the user with impression that Linux is not ready for Desktop use or somehow it is the the Linux distro fault.

After giving an introduction I will continue further to exact problem I've faced with one such mis-configured just today. The same issue has happened in my sysadmin practice over and over again so many times. So finally I decided to write this small story explaining the whole scenario, its causes and fix.

I'm writing this little post from another Linux installation like this which is living on a small local network served by a Vivacom ISP through ADSL Commtrend SmartAX MT882 Router.

The Commtrend does NAT (Network Address Translation)-ting for whole local network, auto-assigning some DNS server to Natted IP PCs local Network addresses in IP raneg; (172.16.0.0-255). The DNS the router assigns for internet is with IP (172.16.0.1), where in reality the DNS on the router is run on Network interface with IP 1921.68.1.1, in other words belonging to the router from another network. Thus PCs connected via a UTP land-line cable connection does not see 192.168.1.1 – meaning Domain name resolving works not at all.
The solution is to assign a static IP address for DNS of Google Public DNS or Open DNS, while leaving the Linux host to automatically assign LAN IP and Gateway using DHCP – (Dynamic Host Configuration Protocol).

By default most Linux distributions use DNS configured in /etc/resolv.conf as a host DNS servers, however as CommTrend Network Router does provide settings for DNS Servers to be used for resolving along with other settings on each Linux host boot settings from /etc/resolv.conf gets ovewritted with the unreachable (from 172.16.0.255), nameserver 192.168.1.1.

Thus to work-around this on most all Linux distributions you can set /etc/resolv.conf to be overwritten adding a line to /etc/rc.local script (before its last line – exit 0);

echo 'nameserver 8.8.8.8' > /etc/resolv.conf
echo 'nameserver 8.8.4.4' >> /etc/resolv.conf

This method is universal, but the problem with it arises, if on the Linux host is planned to run 24 hours a day. DHCP Servers on router has configured DHCP Expiry lease time, which is different on different routers but usually few hours i.e. (4 hrs). Thus in 4 hours, due to DHCP Lease expiry the Linux host will question the DHCP Server for IP, getting together with DHCP IP and Gateway Settings also a DNS IP (overwritting again /etc/resolv.conf – with local running ISP Router IP – 192.168.1.1). One stupid solution of course is to use good old Windows philosophy (reboot it and it will work).

Other little more intelligent but not very efficient solution to problem is to set a cronjob, to run every 1 minute and overwrite /etc/resolv.conf DNS setting.

# crontab -u root -e

*/1 * * * * echo -e 'nameserver 8.8.8.8\nnameserver 8.8.4.4' > /etc/resolv.conf >/dev/null 2>&1

Since the cronjob to overwrite DNS IPs runs every one minute it is possible the host ends up without internet from few secs to 1 minute, this might happen quite rare so for a desktop this is ok. Other inconvenience is it puts a tiny load on system every 1 minute.

Final and best solution is to configure DNS server from /etc/dhcp/dhclient.conf  for Ethernet Interface eth0. Inside /etc/dhcp/dhclient.conf for eth0 make sure you have:

# vi /etc/dhcp/dhclient.conf

interface "eth0" {
prepend domain-name-servers 8.8.8.8;
prepend domain-name-servers 8.8.4.4;
prepend domain-name-servers 208.67.222.222;
prepend domain-name-servers 208.67.220.220;
}

Howto remote access Windows PC which is behind Vivacom ADSL (Commtrend SmartAX MT882 router) modem with VNC server

Wednesday, May 11th, 2011

Reading Time: 4minutes
I had been assigned the not easy task to make a Windows XP Pro which is located behind an ADSL modem to be remotely accessible via VNC

The Windows is connected to the Bulgarian Vivacom Intrnet provider through their ADSL service and hence there is an ADSL router modem which is configured to disallow all inbuond connections by default.

The Windows Pro PC where the VNC server was needed to be accessible did not have a real IP address (e.g. was assigned a virtual IP address by the ADSL modem.

The exact ADSL model used to connect the computer via a lan cable to the internet was Huawei SmartAX MT882

As the device is owned by Vivacom (the ex BTK tele communication company) I did not have any admin user and pass credentials for the ADSL modem to configure the ADSL router to do a port NAT forwarding of port 5800 and 5900 used by the VNC software I installed on the PC (TightVNC)

Nevertheless the missing user and password I decided to check in google if I can find some default passwords that Vivacom ADSL modems are configured to work with

After a few minutes spend in Google I already had found few passwords which were said to work fine with the Vivacom ADSL router.
Here are the passwords I found for the Vivacom ADSL Internet modems:

ZTE ZXDSL 832
username: root
password:GSrootaccess

ZTE ZXDSL 831
username:root
password:GSrootaccess

ZTE
username:root
password:831access

Huawei SmartAX MT882
username:root
password:MT882rootaccess

ZTE ZXDSL-531b
username: root
password:warmWLspot

I tried some old school brute force techniques 😉 by trying all the passwords via the ADSL web interface located on http://192.168.1.1 (I was not sure which model the Vivacom ADSL modem is as on the router there was nothing written concerning the modem type but only the Vivacom logo was present.

After a bit of time I already knew that the ADSL modem model, user and pass was:

Huawei SmartAX MT882
-------------------------------
user: root
pass: MT882rootaccess

My next step was to configure port forwarding for the SmartAX MT882 ADSL in order to achieve from modem’s web administrator I had to follow the menus:

Advanced Setup -> Virtual Servers

ADSL virtual servers menu screen

Next in the NAT — Virtual Servers section I pressed the Add button to create new automatic redirection (port forwarding) rule.

Virtual Server port forwarding screenConfiguring ADSL SmartAX MT882 TightVNC NAT port redirection screenTightVNC requires also NAT port redirection rule for port 5900 in order to be able to connect to the VNC server behind the dsl, so analogically I added a Virtual Server NAT rule for port 5900.

Note that the private IP address of the Windows host was assigned by the ADSL router to the ip 192.168.1.3

Further on I expected the adsl port forwarding created rule would now allow me to connect to the VNC server on the pc located behind the dsl firewall, but I was wrong… even though all seemed to be configured just fine in the ADSL router still the port unmbers 5800 and 5900 were showing up as closed during nmap scan as well as a simple telnet connection to port 5800 and 5900 failed to get established.

My logical assumption was that some configured Firewall on the Windows PC is blocking port connections to 5800 and 5900 thus I decided to check the default Windows Firewall settings as a first possible cause for the vnc ports being blocked.

I did that via the Windows menus:

Start -> Settings -> Control Panel -> Windows Firewall

However weirly enought it seemed the Windows Firewall was disabled e.g. the Off (not recommended) option was set for the firewall.

A bunch of other lookup over all the running system and services on the windows hosts I have found the PC is protected by NOD32 Antivirus – Personal Firewall

The default behaviour of NOD32’s Persnal firewall was extremely restrictive and I found it’s causing a port filter of the 5800 and 5900 vnc connection ports.

To solve the filtering nod32 did I had to open NOD32 and navigate to the following menus:

Setup -> Personal Firewall -> Configure rules and Zones

In the Zone and rule setup menu config window I had to further press on:
New button to add new personal firewall rule.

In the New rule: menu I filled in the following info:
In the General tab:

Name: vnc
Direction: Both
Action: Allow

In the tab Local

I pressed over the Add Port

Number: 5800

in the Remote tab once again I had to fill in:
Number: 5800

Then to confirm settings just pressed OK

Next on I added in the same manner an allow rule for port 5900.

After this settings I restarted the NOD32 firewall to make sure the new settings takes place by pressing over the Personal firewall button Disable filtering: allow all traffic and right after enabling the firewall once again.

Now remote tightvnc connections to the Windows XP Pro pc works like a charm once again, Thanks God 😉