Sunday, August 31, 2008

Network Bridge Wired and Wireless Connections not working

If you have issues in getting to work after trying to the bottom

The Basics ....

The first question to be answered is why would someone want to bridge a wired with a wireless connection. Well the situation in my case was that I have a small network with a router connecting 4 machines. I also have a netgear wireless router serving a couple of laptops elsewhere close by. Now the idea in my mind is that why can't I have internet access for the this small network for basic stuff such as Email, Antivirus etc

So I get myself a USB wireless card which plugs into the USB port of one of the laptops. Now this allows this computer to be part of the LAN as well as part of the wireless network with the laptops but this does not allow the remaining computers to have access to the internet or to the other computers part of the wireless network.

Fortunately Windows XP has an solution for the problems and its called a network bridge. It allows you to create a network bridge on the computer that has access to both networks and allows for cross traffic across both. The concept is well documented in many sites and if you want to set it up would recommend a google search for a more detailed explanation with screen shots. I will briefly explain here.

Assume that the router acts a DHCP Server and is setup to allocate IPs in the range of 196.168.0.x so the systems on that network would have IPs such as 192.168.0.2 / 192.168.0.3 etc The desktop connected through the USB wireless will also have an TCP/IP automatically setup with an IP as 192.168.0.5.

Do a ipconfig in DOS or properties of the connection and note down the DNS settings of this connection.

Now the other network (wired) since its a router you have to physically set up the TCP/IPs. On each of the systems setup the IP as 192.168.0.101 / 192.168.0.102 etc with the subnet as 255.255.255.0 and the gateway as 192.168.0.1 Now the system which has the USB connection as well as the lan connection will be having two networks connected with two IPs say 192.168.0.105 and 192.168.0.5

In the network connections page select the two networks right click and select network bridge. You will be required to enter the details of the bridged network. Use the same setting of the LAN TCP/IP settings for IP , subnet and gateway.

Additionally now the DNS settings need to be setup since the connection has been manually setup. Use the DNS settings you have captured earlier and plug it in here as well as all the other computers that are part of the wired LAN.






Ideally doing all the above should work but unfortunately it didn't after lots of search I came across this setting to force a certain mode on the computer

In DOS type in the following commands

netsh bridge show adapter

-------------------------
ID AdapterFriendlyName ForceCompatibilityMode
---------------------------
1 Wireless Local Connection disabled
2 Local Area Connection disabled
---------------------------

if you get the above output then type the two statements below ...

netsh bridge set adapter 1 forcecompatmode=enable
netsh bridge set adapter 2 forcecompatmode=enable


The "
netsh bridge show adapter" command nows shows the following

-------------------------
ID AdapterFriendlyName ForceCompatibilityMode
---------------------------
1 Wireless Local Connection enabled
2 Local Area Connection enabled
---------------------------


This finally got my bridged network working :)

If you found this useful, do drop me a line.

Thursday, August 21, 2008

Member Hierarchy with Multiple Parents / Many to Many Dimensional Modeling

Over the course of one of my projects this unique issue posed itself that needed to be solved. I needed to build a reporting analysis tool that allowed me to analyze data across various dimensions such as Time / Geography / Product etc. One of the parameters on which analysis was need was on Type. Now Type unfortunately wasn't a one is to one mapping or a many to one mapping.

For example a single store could be Hair Focus outlet , it could also be a Skin focus outlet, a Food focus etc. Also possible that the it could just be one of the above.

Now if we go ahead and build a normal hierarchy with this kind of mapping of outlets to their respective types as defined below it runs into various problems of incorrect totaling.

Outlet Type
1 Skin Focus
1 Food Focus
2 Skin Focus
2 Hair Focus
3 Hair Focus
..
..
..


The problem being if we try and report say sale based on Type it will double count outlets 1 and outlet 2 and the resulting total would be incorrect.

Another typical example of this based on my reading is when in a bank individual have single accounts as well as joint accounts and the same needs to modeled ensuring that we don't end up double / triple counting the same record while reporting balance or any other parameter.

I came across this fantastic white paper, that describes this problem and more importantly the solution to the same.

http://www.sqlbi.eu/Projects/Manytomanydimensionalmodeling/tabid/80/language/en-US/Default.aspx

The issue is treated as a many to many dimension modeling and has a very straight forward solution using SQL Server 2005 and something known as a factless dimension. More importantly it gives insight into how one may be able to model the same and the fundamental principle could be attempted to be used in other schemas as well.

The capability solved my problem of allowing me to create a dimension on the type which allows for navigational / selection and ensuring that no double counting takes place at the total levels.

If you have found this page useful, do drop me a comment.

Wednesday, August 20, 2008

Multiple Remote Desktop Connections (RDC) XP not working

If you have tweaked around with Windows XP you probably know that its possible to connect to another system across a network, intranet / internet as a remote user with the same interface as sitting on the system.

The capability is bundled with XP pro and I'm sure that you will find enough and more blogs / tutorial about how it works with screenshots and all. The issue is that its not available in XP Home and in XP Pro it allows only one user to work on the computer.

Based on my searches I believe its also possible to hack XP Home to support RDC, though I haven't tried it myself the following link does have all the details that you could possibly need to try this out.

http://www.geekport.com/2007/08/15/enabling-remote-desktop-in-xp-home/

http://www.mydigitallife.info/2008/06/14/install-and-enable-remote-desktop-in-windows-xp-home-edition/

Now to the problem in XP pro , as mentioned earlier , the licencing agreement of MS allows only one user to access the computer so if you RDC to a computer the existing user gets logged out (not desirable). There is a way of overcoming this issue with some registry changes and a changed Terminal Service Dynamic Link Library (termserv.dll).

There are detailed article on the procedure available below

http://sig9.com/articles/concurrent-remote-desktop

http://www.mydigitallife.info/2008/06/13/enable-multiple-concurrent-remote-desktop-connections-or-sessions-in-windows-xp/

Additional some good soul has also written a program that neatly makes all these changes and also patches the termserv.dll the link for that is

http://www.kood.org/terminal-server-patch/

For most of the people in the world doing all this worked just fine and if you have tried and are successful good for you .... but then again there are those who are not so fortunate in life such as me who after trying out each and everything on all the links that I have posted including the application got nothing to work. The main user still got logged out each time I tried to RDC to the system.

After more googling I came across this obscure little package called
TermSrvNoRestrPatch-1-3

The location of the file is as following

http://ice-club.com.ua/antiwpa/Other/TermSrvNoRestrPatch-1-3/

which was also a real pain to find a valid link for it. It worked like a charm, it step by step patched all the file which the other application also did but this one got it to work ! It also patched the capability to RDC to a local host, yes there are a few reason why someone would want to do something like this :) such as running multiple instances of a single program.

A word of caution, since the code edits few of the windows' files, some antivirus programs through it up as a virus. You may need to run this in safemode if your antivirus prevents its from executing and more importantly if your convinced that it isn't a virus.

Hope this has helped all the hapless people out there trying to get this to work. As always do drop me a comment if you found this useful, if your feeling generous you could donate a dollar via paypal :)

Monday, August 18, 2008

Ipmsg IP Messenger

If you have a small network and needed to communicate without needed to use the internet or having to set up a communication server the following application is really great. It does not need an installation and can be run whenever needed. It works on port 2425 and automatically picks up other users on the network that are running the application that are part of the same subnet.

The good is that it has a log, quotes the last message in the reply, lets each member be part of a group and puts those people together. Additionally the really cool part is that it supports file transfer including folder transfer as well ....

Its freeware and maintains a small footprint about 5 MB of memory, peer to peer, scalable and almost never interferes with other applications.











The link for the site is below

http://www.ipmsg.org/index.html.en

If you find the post useful drop me a line would love to know.

Cheers,
Vikram.