ENBT Private Network

While updating manuals for EtherNet/IP communication for RSLogix 5000 controllers I stumbled across a change in the 1756-ENBT configuration. In the Ethernet Address field there is an option for Private Network, with the first three octets filled in. When clicked, the IP address option grays out and the last octet of the Private Address can be changed.

This change apparently came in Ver. 18 of RSLogix 5000 software, although it is not mentioned in the release notes.

What is a Private Network in Rockwell usage and where can I learn more about them.

I need some light here. Thanks.
Steam

Welcome to the Forum !

It's not a special thing for RA; it's just an ordinary IPv4 private network range.

The most common IPv4 private network is 192.168.1.x, with subnet mask 255.255.255.0.

Some RA devices that use physical switches for IP addressing use that network range. The RSLogix 5000 designers just tried to make that configuration a little easier to do.

Private network in this case refers to using the 192.168.1.0/24 subnet. It has the same effect as if you typed in 192.168.1 for the first three octets.

This is part of one of three subnets set aside by IANA for private networks.

10.0.0.0 - 10.255.255.255 (10/8 prefix)
172.16.0.0 - 172.31.255.255 (172.16/12 prefix)
192.168.0.0 - 192.168.255.255 (192.168/16 prefix)

These addresses are not globally routable so they cannot be directly addressed from the internet (for better or for worse).

See RFC 1918 for more information about private networks.

Thanks. I'm familiar with the 192.169.x.x format.
So, this isn't a special network with security features but rather a short cut to keep from having to type 12 numbers? It means a lot of screen caps to re-do.

192.168.x.x, not 192.169.x.x

I've never heard of it referred to as a "special network with security features", but that's not a bad way to think of it. As Ken and Timbert suggested, RFC 1918 suggests that the address range (and 2 other others) are designated for "private" use. This means that Internet routers, by default and convention, will respect the range and not pass that traffic. Your router is the only one that should, through the use of "Network Address Translation", which allows multiple nodes to share an IP address, plus provides some degree of "free" security. Using this address range is more of a "best practice".

Steam_PLC said:

Thanks. I'm familiar with the 192.169.x.x format.
So, this isn't a special network with security features but rather a short cut to keep from having to type 12 numbers? It means a lot of screen caps to re-do.

Click to expand...

Thanks to all who responded to my question. Having worked with AB communications since Interchange, I feared they had come up with some new "feature" with visions of propriatery VPNs running through my head. Are we getting so dumbed down that we can't type 12 numbers? And what control engineer does not know that 192.168.x.x is the preferred IP address for in-house networks? I guess I over thought the issue.

I would still like to know where those of you who posted replies got your information from AB. I'd like to read what they have to say on the subject because I know I'm going to get questions about it.