Is it possible OpenDNP3 can open multiple Outstations on the same server

[Lee Derting]

Hi, 

Is me again. 

I have a question on yesterday, is related to Abnormal connection on aws network load balancer (https://groups.google.com/forum/#!searchin/automatak-dnp3/aws%7Csort:date/automatak-dnp3/tnO0J8ooSJM/Lo7r3LFdAwAJ).

Today I have another more important question.

「Is it possible OpenDNP3 can open multiple Outstations on the same server?」

I using Dotnet examples Program (https://github.com/dnp3/opendnp3/blob/release/dotnet/examples/outstation/Program.cs). 

Open two programs, and setting like that:

Outstation A:

First program-> IP: 0.0.0.0, Port: 20000, Source: 10, Destination: 10

Master A:

First program -> IP: 0.0.0.0, Port: 20000, Source: 10, Destination: 10

At this moment all is good, MasterA and OutstationA is connecting.

and go on setting Outstation B

Second program-> IP: 0.0.0.0, Port: 20000, Source: 20, Destination: 20

Master B:

Second program -> IP: 0.0.0.0, Port: 20000, Source: 20, Destination: 20

I observe that the channel state goes from Open to Closed to Open. 

...

2020/7/10 下午 06:39:03 - server - WARN - Frame w/ unknown route, source: 20, dest 20

2020/7/10 下午 06:39:04 - server - INFO - Accepted connection from: 127.0.0.1

Channel state: CLOSED

Channel state: OPEN

2020/7/10 下午 06:39:05 - server - INFO - Accepted connection from: 127.0.0.1

Channel state: CLOSED

Channel state: OPEN

2020/7/10 下午 06:39:05 - server - WARN - Frame w/ unknown route, source: 20, dest 20

2020/7/10 下午 06:39:06 - server - INFO - Accepted connection from: 127.0.0.1

Channel state: CLOSED

Channel state: OPEN

2020/7/10 下午 06:39:07 - server - INFO - Accepted connection from: 127.0.0.1

Channel state: CLOSED

Channel state: OPEN

...

Why is this so?

I'm pretty sure OpenDNP3 Simulator (v2.0.X) can work in this case.

Please let me know what should I do. 

Thank you.

Derting

[Adam Crain]

DNP3 servers (outstations) are not stateless. They maintain event history for a particular master station even when the client is disconnected. This

is why you can only accept a single connection. If you need to allow multiple masters to connect, then create two mirrored outstations on two

different ports.