5380 Compact GuardLogix DNS disabled on port A2 in dual IP mode

ASF

Lifetime Supporting Member
Join Date
Jun 2012
Location
Australia
Posts
3,907
I have a 5069-L306ERS2 set to dual IP mode. Both ports are set to static IP address and have different IP addresses, subnet masks, and gateways configured. However, on port A2, the DNS server and domain fields are greyed out and I can't see any way to enable them. Port A1 is fine; it has the DNS/domain entered and working; though port A1 was configured second, so I don't believe it's a case of "whichever one you configure first is the only one you can configure".

Is there some restriction about only being able to set up DNS/Domain on port A1 in dual IP mode? I can't find anything on the knowledge base or the manual, but perhaps I'm just not using the correct search terms.
 
Check the user manual, Dual-IP mode described there:
Only A1 is for enterprise network, and has DNS enabled.
A2 is for Device network only.
 
I'd also check your gateway config. Don't think you should really set a gateway on both ports. Not entirely related to your post, but just read your config.
 
Gateway is definitely required on both ports as both ports need to communicate to equipment on different VLANs
 
I'm curious why Rockwell doesn't let you set both interfaces to use IP addresses on the same subnet.
My guess is it will have the same effect as if you set two computer NIC’s on on the same subnet, processor will be confused what port to send it to. Again, just a guess.
 
My guess is it will have the same effect as if you set two computer NIC’s on on the same subnet, processor will be confused what port to send it to. Again, just a guess.
That’s true on a desktop OS where it has an internal routing table and their applications (generally) aren’t configurable to do use specific interfaces, but the AB PLC does CIP pathing first (embedding the IP in one of the path segments), so the port it uses is always explicit and determined.
What would be the benefit of that?

I’m not suggesting it be a thing (just curious by dint of limitation), but I suppose you could use one of the NICs to be the “programming port”/uplink and the other be dedicated to I/O traffic if a customer wants a single IP subnet.
 
Which gateway has the higher priority? How does the CPU know which gateway knows unknown network?

It doesn’t work that way. When the controller receives a packet from a remote subnet on a given interface, the gateway address configured for that interface is where the response packet is sent to be carried onto the next hop. The router at that address contains a routing table to know where to send it next.

If you were to attempt to connect to a PLC on a remote subnet without it having a configured gateway address, the PLC would receive your packets to establish connection but have no idea where to send response packets, for example.
 

Similar Topics

gents, I am trying to configure communication with EMERSON PK300 controller through port A1 using generic ethernet communication module . I could...
Replies
0
Views
19
I had a comms fault between my VFD and Controller (5069-L320ERS2) that started about a month ago and happened maybe once a day to now where it...
Replies
1
Views
244
I have a 5069-L320ERS2 that has the scrolling LCD screen on the front. Is there any way for me to see what message is being displayed on that...
Replies
2
Views
1,723
Hello, I am trying to install the Firmware in a Compact GuardLogix 5380 PLC. I am running RSlinx Classic and controlFLASH on a virtual Windows...
Replies
3
Views
2,547
Evidently I'm not straight with this... If you do an program edit, and do not re-save the file to the flash card, when do you risk booting up the...
Replies
1
Views
1,808
Back
Top Bottom