SQL Server and Multiple IP Addresses
Posted on 2013-01-25
This question is possibly mainly to do with networking and IP Addresses, but it is particulary with respect to connecting to SQL Server databases.
I am developing an Access 2007 "project" (.ADP) as a front end to data stored in a SQL Server 2005 Express database. I do the development work on my Windiws XP laptop at home (that runs both Access and SQL Server), then use "Remote Desktop Connection" to send an ".ADE" version of the Access program to my client's Windows 2003 Server computer, from where it is copied down to all their users' PCs.
I feel that an IP Address in the Access application's "Connection string" seems to produce a better performance than a computer name. ie "192.168.1.1\SQLEXPRESS" seems better than "JC-SERVE05\SQLEXPRESS".
On my small network at home (my Windows XP laptop, a Windows XP desktop PC, and a Virgin Media "Super Hub" that acts as a DHCP server and connects with my cable broadband service to the outside world) I have named my own desktop PC (which also runs SQL Server) "JC-SERVE05" so that it has the same name as my client's Windows 2003 Server computer. This means I can easily create an ".ADE" file with a "JC-SERVE05\SQLEXPRESS" "Connection string" before I copy it across to my client's site.
This all works OK so far. When my client's users launch the ".ADE" file on their computers it connects with the SQL Server instance on their "JC-SERVE05" server. What I would like to do is start to use an IP Address in the "Connection string". The IP Address of my client's server PC in their ware house is 220.127.116.11 but I seem to be unable to assign that IP Address to the desktop PC on my home network.
Before I ask their IT people if they can change their server's IP Address to something like 18.104.22.168 so that it matches a value I can also have at my end, I thought I would investigate the option of assigning multiple IP Addresses to a single Ethernet card.
This appears to be possible using Windows XP's "Network Connections" utility but you have to disable the "DHCP acquisition" option. Adding two IP Addresses to one computer on my home network has mixed results. Although I can successfully "ping" both IP Addresses from the other computer, I can only successfully use one of the IP Addresse in a "Connection string". The connection to the SQL Server works only with one and not the other. Also, the computer that has been assigned the two IP Addresses can no longer access the internet (presumably still via my Virgin Media "Super Hub" that is still working as a DHCP server) despite retaining the same "Default Gateway" value which is the IP Address of the "Super Hub" itself, and also being seen as connected to the local network when I log on to the "Super Hub" and use its utility programs.
I am perhaps being a bit naive here, and hopefully someone can set me straight. Two specific questions I guess :
1. Why does the Access-SQLServer "Connection string" only work with one of the IP Addresses assigned to a host computer and not with them both?
2. Why is the computer with the two IP Addresses blocked from accessing the outside world?
Any help gratefully received. Thanks.