No response from NX701 behind intranet firewall router

3 posts in this topic

I use Netgear routers with multi-NAT capability to attach machines to the company LAN. One of the advantages is that similar machines can have identical network addressing schemes while a multi-NAT router on each machine can be used to assign unique external addresses. The usual error on these setups is to forget to assign a gateway IP address and so the PLC can't respond to requests from outside its subnet.

  • I have the router set up as normal (as I have done a hundred times before on other machines).
  • PLC has correct IP address, subnet and gateway (that of the router LAN address).
  • Router has NAT rule configured, correct LAN subnet, etc.
  • I can PING the PLC from the company network. This implies that the router, wiring, etc., are all OK.
  • If I disconnect the PLC ethernet cable during a PING I get errors. This implies that the address is unique, etc.
  • Controller --> Communication Setup --> Ethernet connection via hub --> Ethernet communication test --> "A communication error has occurred."

Has anyone seen this? Any reason why it shouldn't work as I expect?

Many thanks.


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Did you try to go online with the controller as well?  I have seen where the test can fail, but it is still able to connect.

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I tried to go online as you suggested but that failed too.

I can connect locally but I'm having trouble transferring the program. See my other post, if you have time.


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