Confused 1756 ENBT

omit the word 'port' and just use a space to designate the TCP Port number.

tcping 10.24.9.251 2222
tcping 10.24.9.251 44818

Those are the two TCP Port numbers for CSPv4 and EtherNet/IP.

One of my other favorite sleuthing programs is NMAP; I use the Windows GUI version:

http://nmap.org/zenmap/

You can point NMAP at an IP address and let it do a query and it will tell you all about the target.

I still think we're fighting a duplicate IP address on a computer, here.

C:\>tcping 10.24.9.251 2222
Probing 10.24.9.251:2222/tcp - Socket is not connected (10057) - time=2001.517ms
Probing 10.24.9.251:2222/tcp - Socket is not connected (10057) - time=2000.118ms
Probing 10.24.9.251:2222/tcp - Socket is not connected (10057) - time=2001.402ms
Probing 10.24.9.251:2222/tcp - Socket is not connected (10057) - time=2000.489ms

Ping statistics for 10.24.9.251:2222
4 probes sent.
0 successful, 4 failed.
Was unable to connect, cannot provide trip statistics.
C:\>tcping 10.24.9.251 44818
Probing 10.24.9.251:44818/tcp - Port is open - time=6.208ms
Probing 10.24.9.251:44818/tcp - Port is open - time=3.508ms
Probing 10.24.9.251:44818/tcp - Port is open - time=1.774ms
Probing 10.24.9.251:44818/tcp - Port is open - time=3.819ms
Ping statistics for 10.24.9.251:44818
4 probes sent.
4 successful, 0 failed.
Approximate trip times in milli-seconds:
Minimum = 1.774ms, Maximum = 6.208ms, Average = 3.827ms
C:\>

Your RSLinx Classic event log showed the device accepting a TCP connection on Port 2222 (the CSPv4 protocol) but TCPing shows it rejecting a connection on that port.

This suggests that something has changed.

Or there's something bizarrely weird going on with your network, or you have some strange and beautiful mutation of firmware in the 1756-ENBT.

If this were my system, I would use Wireshark to get to the bottom of this. Delete the Ethernet devices driver, then while running Wireshark create a new one (just the IP address, not the :EIP suffix) and browse with RSWho.

In that screenshot, the name 'Trim_AB' shows up. Is that a name associated with that controller ?

Does your network include any routers, or dial-in modems, or otherwise devices that might re-direct a connection from the 1756-ENBT to something else ?

So......it is not seeing port 2222, which is CPSv4.....

Interesting...a while ago I added the :ETH in the driver config, 10.24.9.251:ETH....I just removed it and now it does not show Tim_AB, it has changed to AB_ETH-M.....The controller name for each machine is MMAP...

Are you absolutely sure that your own computer's IP address does not conflict with the controller ?

The 'Computer' icon, the acceptance of CSPv4, and the device name all point to a PC running RSLinx conflicting with the 1756-ENBT.

No...it is not my Laptop IP but C@*&%......it is in my advanced TCPIP settings......so in effect it is my IP.......
Removed that IP from my advanced settings and it is now fine.....
From day one I thought it was a IP conflict.....

Guess it really was...

Thanks for your help...

I've been bitten by Virtual Machines running on my PC having the same IP as my controller before, and stood there dumbfounded with two cables going into the switch, yet detecting three devices.

Thanks for posting the followup !

ARP -A was a Huge Help

This helped me out tremendously. I have been trying to figure out what is causing my 5/05 to drop out daily at 12:00 pm and without the ARP -A command, I wouldnt have figured it out. WireShark was not reporting anything helpful, Thank you for the post.
My conference room Vizio TV after 3 years of being on the wall, all of a sudden started grabbing the same IP as my PLC! Who'd a thunk it!

Dear colleges

I'am pulling this old thread out of history because I had yesterday an network issue which looked totally the same for me when I had a look in the Log files of my 1756 - EN2T Card.

03/03/22 13:36:49 XXX.XXX.1.70 Device refused a CSPv4 connection, retry using EtherNet/IP
03/03/22 13:36:49 XXX.XXX.1.70 Attempting first connection, protocol = EtherNet/IP
03/03/22 13:36:49 XXX.XXX.1.70 Device has accepted the EtherNet/IP connection
03/03/22 13:36:49 XXX.XXX.1.70 Can't set port type to 288: no Harmony object for this Ethernet
03/03/22 13:36:59 XXX.XXX.0.30 Attempting to reestablish a lost EtherNet/IP connection
03/03/22 13:36:59 XXX.XXX.0.30 Device has accepted the EtherNet/IP connection
03/03/22 13:36:59 XXX.XXX.0.30 Can't set port type to 288: no Harmony object for this Ethernet
03/03/22 13:36:59 XXX.XXX.0.30 Error receiving data from the Ethernet Interface
03/03/22 13:36:59 XXX.XXX.0.30 [10054] Connection reset by peer
03/03/22 13:36:59 XXX.XXX.0.30 EtherNet/IP connection has been lost
03/03/22 13:37:09 XXX.XXX.0.30 Attempting to reestablish a lost EtherNet/IP connection
03/03/22 13:37:09 XXX.XXX.0.30 Device has accepted the EtherNet/IP connection
03/03/22 13:37:09 XXX.XXX.0.30 Can't set port type to 288: no Harmony object for this Ethernet
03/03/22 13:37:09 XXX.XXX.0.30 Error sending data to the Ethernet Interface
03/03/22 13:37:09 XXX.XXX.0.30 [10054] Connection reset by peer
03/03/22 13:37:09 XXX.XXX.0.30 EtherNet/IP connection has been lost

I tried all the troubleshooting steps from this post. In the end it was a huge amount of TCP connections which was flooding my EN2T Card because we installed a bunch of new servers and put them online without telling anybody.

I was able to see this in the normal diagnostics webpage of the EN2T card. After the servers where shuted down, everything was working back normal and now more errors in the error log.

Kind regards Michael