Network Mapping issue

[Rosco]

I have a big client under contract 15 pc and a server. Anyway they are dissolving in November so they are kind of jumping around with techs. They hired their pervious tech(because they are cheaper.) Anyways they use turbo law, abacus, and a few others. It all works off the server. Last time i was in it was fine. I monitor it with gfi max. Now there is an problem. They were have trouble at times connecting to the mapped drives on the server. The other tech was called and "fixed the solution" by mapping them to the servers IP address . they could now always connect but their software can not connect. They have talked extensively with the tech support and they said it had to be mapped by the computer name. "mainserver". Now the pcs will not let me choose the mainserver when i try to map the network location or type it in manually.

I have checked all the settings and everything looks normal server and workstation sides. Any ideas. thanks.

 

[YeOldeStonecat]

My first hunch is "DNS".
Hopefully the "server"...if it is indeed a Server operating system and running as a DC, is using itself for DNS.
And hopefully it is doing its job as a server and running DHCP
And hopefully DHCP is handing out the servers IP address for DNS...nothing else..unless there's a second DC.
And hopefully the workstations are "pro" versions of Windows...and not stuff like Windows Home Edition.

Hopefully the router isn't doing DHCP handing out itself or the ISPs servers for DNS.

 

[Rosco]

My first hunch is "DNS".
Hopefully the "server"...if it is indeed a Server operating system and running as a DC, is using itself for DNS.
And hopefully it is doing its job as a server and running DHCP
And hopefully DHCP is handing out the servers IP address for DNS...nothing else..unless there's a second DC.
And hopefully the workstations are "pro" versions of Windows...and not stuff like Windows Home Edition.

Hopefully the router isn't doing DHCP handing out itself or the ISPs servers for DNS.

Yes it is a real server with server 2008 r2. All the computers are running xp pro or windows 7 pro. The server is the DC and running as a dns. It is the only one that has a static IP. The rest of the computes obtain everything automatically.

ANy tips on how to drill done to the core of the problem? thanks

 

[YeOldeStonecat]

I would want to see the results of an "IPCONFIG /ALL" from a few workstations. Until then...it's only spending time and guessing.
failure of name resolution nearly always points to DNS.

 

[MobileTechie]

Is it happening on all machines or just some?
Can you ping the server by name?

Anyway, like stonecat says - you gotta check the basics to see it's even running as one would expect before going any further. You might find out there are fundamental DNS issues.

 

[Rosco]

Sorry i have been in and out but here is a screen shot of the ipconfig all from a work station. I was able to ping the mainserver by name.

 

[YeOldeStonecat]

Can't stretch enough to read...too small.

 

[Rosco]

Here is a bigger one. It is happen across all computers to. I can see it in the network part of windows explorer just cant click into it.

 

[YeOldeStonecat]

Got your answer now....

Notice the first 2x DNS servers? Those are Comcasts.
Notice the 3rd DNS server? That's the LAN IP address of Comcasts SMC gateway, the combo modem/router.

None of those belong there.

Making things even scarier....the network appears to be behind a router, 192.168.1.xxx...which is behind the SMC appliance....so that's probably double NAT'd. (since they stuck the SMC as the 3rd DNS server).

Someone redid the DHCP on that network on you..and butchered things up with a very amateur mistake by someone that doesn't know about active diretory and DNS. You said this client went with the cheaper guys...now they need to realize what going cheap got them.

Server should be running DHCP and DNS for the clients, nothing else!

The outcome was exactly as I predicted!

 

[Rosco]

Got your answer now....

Notice the first 2x DNS servers? Those are Comcasts.
Notice the 3rd DNS server? That's the LAN IP address of Comcasts SMC gateway, the combo modem/router.

None of those belong there.

Making things even scarier....the network appears to be behind a router, 192.168.1.xxx...which is behind the SMC appliance....so that's probably double NAT'd. (since they stuck the SMC as the 3rd DNS server).

Someone redid the DHCP on that network on you..and butchered things up with a very amateur mistake by someone that doesn't know about active diretory and DNS. You said this client went with the cheaper guys...now they need to realize what going cheap got them.

Server should be running DHCP and DNS for the clients, nothing else!

The outcome was exactly as I predicted!

Thanks oldstonecat. what would be the best way to start untangling this mess?

Yes they are behind the router.

 

[YeOldeStonecat]

Do you have remote access to the inside router..and to the server?
I'd flip on DHCP on the server..and set it up to hand out the servers LAN IP for DNS, the router for the gateway, define the IP hand out range, enable netbios over IP, set your exclusion range, authorize the scope, etc.

 

[Rosco]

Do you have remote access to the inside router..and to the server?
I'd flip on DHCP on the server..and set it up to hand out the servers LAN IP for DNS, the router for the gateway, define the IP hand out range, enable netbios over IP, set your exclusion range, authorize the scope, etc.

What should i change on the router it is a Linksys BEFSR41

it is set up as a nat

dhcp is enabled

and is running a static IP address from comcast.

 

[SAG]

Disable DHCP on the Linksys
Linksys LAN IP should be like 192.168.1.254 (for instance)
Static IP of Mainserver 192.156.1.5 (for instance)
If Mainserver once ran DHCP and DNS it might still be configured and just need the switch flipped.
If the config was obliterated it can be setup within a few minutes..
Make sure DHCP hands out 192.168.1.5 as primary DNS and 192.168.1.254 as router (for instance).

 

[YeOldeStonecat]

Here is a guide I wrote years ago at a site I helped staff, using Small Business Server 2003. It's a very old guide...but the principles still hold true.

http://www.speedguide.net/articles/server-based-network-guide-1660

I'd upgrade that BEFSR41...that's their first generation router from the early days of broadband, it's a bottleneck on Comcasts connections, and not up to current specs with a kajillion other things.

Leave DHCP enabled on the SMC.
Make sure you log into the SMC and have a check in the box for "disable firewall for true static IP subnet"
Your other router (like the Linksys)...should have the first usable public IP from the Comcast block statically set on its WAN interface

I prefer never to use the common 192.168.0.xxx and 192.168.1.xxx subnets for biz networks...but since it's all there, just leave the Stinksys router at 192.168.1.1, but make sure DHCP is disabled on the router.

Assuming your server has a LAN IP of 192.168.1.10, have its DHCP hand out from 192.168.1.100 to 192.168.1.200, 255.255.255.0 subnet, gateway of 192.168.1.1, DNS of 192.168.1.10.

I'm not sure if you'll have to install the DHCP service, or it's already there and just disabled, or what. It won't fire up if it still detects another DHCP service from the router, so make sure you kill DHCP on the router before firing up the DHCP setup wizard.

 

[Rosco]

Just wanted to give everyone an update.

I went in today. Fixed the DNS and Dhcp, Took Dhcp off the router. Had to remap everything. But it all worked out.

If they had call me to begin would have been a much smaller bill. You get what you pay for with computer repair. I might charge more but at least it is right.


Thank you everyone for your input.

 

[SAG]

I might charge more but at least it is right.

...but at least it is right.

...it is right.

And right there is your sticking point.

 

[Rosco]

And right there is your sticking point.

thanks for the support! appreciate it