Ethernet..... Mask, Gateway and DNS

My I.T. department is asking me a few questions... as I think they are changing the Network so they would like some information on the PLC's, the only thing I know is the IP address that I assign them

Can anyone tell me what Mask, Gateway and DNS are (in our terms) as I have tried searching the net and found a bunch of &^@#*^&)@!@ but nothing that will help me with PLC's

When I look at the settings (on the devices) I can not find any information for what they are looking for.

On the network I have ControlLogix, Red Lion G3's, Automation Directs DL06's, and RSViews

So I guess do I have a Mask, Gateway or DNS?

Many thanks
Mark

Mark,

Some devices may have all those things, some probably do not.

Mask
Subnet mask is used to partition the network into smaller sections. Example: If the subnet mask is 255.255.255.0 then 168.192.1.100 can talk to 168.192.1.101 but not to 168.192.2.101. There is plenty on the net about this topic.

Gateway
The (usually one) IP address on your subnet that can reach other subnets. Pcs almost always have this unless they are in a small workgroup with no servers. PLCs that are all on the same subnet may not use it. There are many out there with this field blank.

DNS
Domain Name Server is a service usually running on a server pc that translates "computer names" into IP addresses. We rarely use these in automation, and usually stick to hard IP addresses.

My apologies to the IT geeks out there, I did not do full justice to any of those topics.

Mask - is the subnet mask, which indicates how many actual 'hosts' (devices) there can be on your particular network.

DNS - is the Domain Name Server, which is responsible for resolving hostnames into IP's. When you look for 'www.yahoo.com', a Domain Name Server (actually, several of them) resolve that into the actual IP of
69.147.114.210. (much easier to remember, but of course you could just type http://69.147.114.210 , and go to the yahoo home page).

Gateway is the IP address of a router on your local subnet, that handles trying to resolve addresses that are NOT on your local subnet.

More detailed resources:

http://www.cit.cornell.edu/computer/support/subsubnetting.html

http://www.bleepingcomputer.com/tutorials/tutorial37.html

http://www.isoc.org/briefings/019/

Thank you both very much... I understand it much better now

Mark,
To answer your question most directly - your IP PLCs will necessarily have both an IP address and Subnet mask. The rest are only important if the PLCs are drawing services from other networks.

All other answers are relevant. It's good info to understand and not nearly as complicated as some make it out to be. I've been meaning to write a short functional TCP/IP explanation for industrial folk. Maybe someday...sigh...

surferb said:

I've been meaning to write a short functional TCP/IP explanation for industrial folk. Maybe someday...sigh...

Click to expand...

If that someday ever comes... please link it here as I would like to read it

Thank you

Sure, I'd love to. That kind of request prompts me to be more interested in writing it. Been working on training videos for Inductive Automation lately...

geniusintraining said:

If that someday ever comes... please link it here as I would like to read it

Thank you

Click to expand...