fortypoundhead.com

Mikel

Joined:
2013-01-01
00:00

Last Seen:
Unknown
Unknown

Posted on:
2008-10-10
11:08

Precautions for changing subnet mask?

Report Back to Forum Back to All Forums

I work at a waste water treatment plant in the Operations department which has a Windows 2003 server. There are two subnets in use, one which is 10.1.1.xxx and the other 192.168.1.xxx. The second subnet is used by the SCADA system which monitors the activity of all the machines that treat the waste water. In a separate building is the administrative staff, which has a separate Windows 2003 network and IP addressing scheme. The subnet there is 192.168.0.x. We are planning on setting up a two-way trust to allow the two networks to communicate through the SonicWALL firewalls in use at both locations. I found that the best way to have the two separate subnets co-exist on the same network is to change the subnet mask to 255.255.254.0, but what I would like to know is: Are there any precautions to keep in mind when modifying the subnet mask?

FortyPoundHead

Joined:
2005-01-01
10:58

Last Seen:
2016-03-27
05:11

Posted on:
2008-10-10
14:22

Report Back to Forum Back to All Forums

They should be able to communicate just fine the way they are, with 255.255.255.0.

Testing in my lab with this config shows no problem:

Building A - 192.168.0.x
Building B - 192.168.1.x

Subnet on both: 255.255.255.0

Both buildings firewalled.

You'll be punching a couple holes in the firewall at both locations to set up the trust, though. IIRC, it is 135, 137,139, and 389. But not sure - I'll have to check that.

Check connectivity by attaching to a share on a remote machine:

Start, Run.
\\Machinename\Sharename

If you get an authentication box, then the path is open. If you are getting in to the share straight away, you have some credentials cached. Again, path is open.

If you get a loooong pause, then a "Not Found" error, then you have some other issues going on.

You must be logged in order to post a reply.




Recent Forum Posts

Advanced search added
dwirch posted on September 23, 2017 at about 13:44 in Site News

Job Spammer: Gaurav Mehta - AgreeYa Solutions
dwirch posted on September 22, 2017 at about 10:35 in Spammers

Job Spammer: Prutha Siri - Javelin Systems
dwirch posted on September 10, 2017 at about 6:15 in Spammers

New security implemented
dwirch posted on September 7, 2017 at about 7:16 in Site News

Malicious IP Checker Companion Tool
dwirch posted on August 12, 2017 at about 20:24 in Site News

Job Spammer: Steve Adams
dwirch posted on August 8, 2017 at about 7:44 in Spammers