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SQL connection

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9 replies

by wraidy

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Hello,

I have 2 sql server on 2 different domain but there's ping between both sites.but suddently the 2 servers stopped to get connected to each other both can't connect either by NAme of the serve or by IP .

I checked my access-list by i everyhtign is allow.

Can some advise

9 replies

by mamies

I would also be looking at the firewall as well. Infact their is probably a number of issues that could stop this

by wraidy

I gave it permit IP any any and i can ping telnet ip 1433 i've been told it's used by sql connection is there 's any other thing to make sure or other port number but the think is nothing changed on the network and the 2 sites are connected by a core swith and then tunnel on the router in both sites and on my sitch the vlan can permit both IP

But can you kinldy suggest a test to make sure 100 % ?

by wraidy

The thing that changed is that i think i have a DNS problem.
because i tried Telnet ip 1433 on the both server and they can connect to each other and as i know it's the protocol used for sql connection.
but i don't have a name resolving between both sites i can access there sites using \\Ip but not \\servername i think it's affecting the SQL server .
I added an entry in DNS in my site but still not working could it be from the DNS in the other site if the DNS is not working there and mine is working with the entry of his server can i still connect by server name..

Please advice because i need to weel define the problem.Thanks in advanced

by tony hopkinson

??????

From 2000 onwards you could have more than one instance on each sql server, all 1433 and now 1434 does is resolve the instance name (default MachineName/MSSQLServer).

Then there's surface re config, windows fire wall, routing/switching, hardware fire walls. Service pack collisions, particularly pre 2005.

I've seen all sorts of reasons why connections were refused. If it's one server to another, then there's remote servers to consider as well.

If you can't answer the question 2000 or 2005/2008 any help you get will be down to extreme luck.

by wraidy

Dear Scott,

i tried an entry on the DNS as you suggested on one site by creating a Hostname and it didn't work shall i create same hostname entry on the DNS of the other site or can it stoped if the other DNS is not working

by tony hopkinson

introduced in SQL 2005.
.Net ADO connection query the browser and get a dynamic port for the instance.
Previous to that DNS.exe implemented SSRP protocol for same (ish) purpose.

There are masses of things that can break connectivity depending on your set up. But something must have changed for it to break suddenly.

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