Friday, March 23, 2012

name resolution (WINS/DNS)

How does the name of a datasource get resolved?

I have a situation where users with notebooks work in several different sites- and need to connect to the database server in the current location, rather than connection to the DB in their 'home' location which is over slow WAN links
. Rather than setting up multiple static database connections (difficult to manage & difficult for users) I hope to use WINS/internal DNS to resolve a hostname to the correct IP address/database server for each location.

For example, the database connection would be something like:

defaultdsn=DRIVER=SQL Server;UID=***;PWD=***;DATABASE=DB1;SERVER=DBSERVE R\DB1

For location 1:
192.168.150.6 DBSERVER

For location 2:
192.168.161.8 DBSERVER

For location 3:
192.168.162.8 DBSERVER

If I use WINS at each location as above, the hostname gets resolved & can be pinged.

However- for the database connection, I cannot make a connection using this approach- I've tried different combinations of named pipes etc etc.

thanks in advanceRE:
How does the name of a datasource get resolved? I have a situation where users with notebooks work in several different sites- and need to connect to the database server in the current location, rather than connection to the DB in their 'home' location which is over slow WAN links. Rather than setting up multiple static database connections (difficult to manage & difficult for users) I hope to use WINS/internal DNS to resolve a hostname to the correct IP address/database server for each location. For example, the database connection would be something like:
defaultdsn=DRIVER=SQL Server;UID=***;PWD=***;DATABASE=DB1;SERVER=DBSERVE R\DB1
For location 1:
192.168.150.6 DBSERVER
For location 2:
192.168.161.8 DBSERVER
For location 3:
192.168.162.8 DBSERVER
If I use WINS at each location as above, the hostname gets resolved & can be pinged. However- for the database connection, I cannot make a connection using this approach- I've tried different combinations of named pipes etc etc.
thanks in advance

S1: Aspects of the situation strike me as potentially 'radioactive'.
S2: I strongly suggest you work closely with your friendly network engineer e.g. (look out for looping and things like that), and carefully test whatever schemes you test / work out (working toghther). What will work depends on how the entire environment is configured. Be sure to take into full consideration any and all things that might be involved or interact with potential solutions at any level, e.g.(like VPNs, dial ups, and other connections between sites).
S3: Alternative general approaches that may be workable (or not, and in any event potentially reckless, if you just 'dive in'):
i) Add site logon scripts that strip any locally cached and/or stored references to DBServer from when the (roaming laptop) was at other sites e.g.(including dsns, added routes, Hosts, lmhosts, arp, etc. data and other entries that may be applicable in your environment).
ii) Bind all the ips of the various DBServers to each and every DBServer.sql

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