# Communication port

**URL:** <https://forum.inductiveautomation.com/t/communication-port/39212>\
**Category:** Ignition\
**Tags:** ignition80\
**Created:** [September 30, 2020, 12:51am UTC](https://forum.inductiveautomation.com/t/communication-port/39212 "2020-09-30T00:51:51Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![zju\_yj](https://avatars.discourse-cdn.com/v4/letter/z/5f8ce5/32.png) [@zju\_yj](https://forum.inductiveautomation.com/u/zju_yj)\
**Post date:** [September 30, 2020, 12:51am UTC](https://forum.inductiveautomation.com/t/communication-port/39212/1 "2020-09-30T00:51:51Z")

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Hi Guys,

I’m setting up the communication between two ignition gateways using default port 62541 to get the OPC tags from RSlinx OPC DA server through OPC tunnel function. I would like to simulate the communication interruption to check the data integration status. When I disabled the port 62541 at both server firewall and security group of AWS EC2, and confirmed the telnet can’t get the remote server response, however, the two gateways are still working well. Can anyone please explain this? or OPC UA used other protocol or ports after established communication here? thanks

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**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [September 30, 2020, 12:53pm UTC](https://forum.inductiveautomation.com/t/communication-port/39212/2 "2020-09-30T12:53:59Z")

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Maybe setting up the firewall rules in AWS doesn’t affect existing connections?

I assume you added an OPC UA connection in the non-tunneler gateway pointed to the tunneler gateway. If you edit/save this connection after the firewall changes what happens?

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [September 30, 2020, 1:22pm UTC](https://forum.inductiveautomation.com/t/communication-port/39212/3 "2020-09-30T13:22:04Z")

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> [@Kevin.Herron](#):
>
> Maybe setting up the firewall rules in AWS doesn’t affect existing connections?

Almost certainly this. Typical firewall rules include a short-cut pass for [Established,Related] connections, since TCP connections are not (usually) conducted on the port used to open them.