# OPC-UA server and two NICs

**URL:** <https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880>\
**Category:** Ignition\
**Created:** [December 16, 2024, 3:05pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880 "2024-12-16T15:05:10Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Ian\_McArdle](https://avatars.discourse-cdn.com/v4/letter/i/f1d935/32.png) [@Ian\_McArdle](https://forum.inductiveautomation.com/u/Ian_McArdle)\
**Post date:** [December 16, 2024, 3:05pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880/1 "2024-12-16T15:05:10Z")

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I have Ignition installed on an industrial PC that has two NICs. I think it's a fairly common scenario - the customer database is on their corporate network and the PLC is on the control network. Both need to communicate with Ignition.

I have tested the connection to Ignition's OPC-UA server using a laptop running UAExpert connected on the corporate network, and this works fine.

I wanted to do a similar test by connecting that same laptop on the control network, but it cannot see the OPC-UA server.

The laptop has a different IP address for each network but even though I added both IP addresses into the OPC-UA server binding settings, I am unable to connect from the control network.

Anyone have any suggestions how to make this work? I'm not sure what's blocking it - I tried temporarily disabling the firewalls to eliminate that potential cause but it didn't fix the problem. I continue to get a "Bad Timeout" during the discovery process in UAExpert.

Is it necessary to bridge the two networks, somehow?

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**Author:** ![michael.flagler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/michael.flagler/32/26272_2.png) [@michael.flagler](https://forum.inductiveautomation.com/u/michael.flagler)\
**Post date:** [December 16, 2024, 3:13pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880/2 "2024-12-16T15:13:19Z")

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Easiest way is to use `0.0.0.0` for the bound IP. This binds all network connections on the PC so they can be connected to from anywhere.

Edit: @pturmel gives an even better explanation and solution below.

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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:** [December 16, 2024, 3:13pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880/3 "2024-12-16T15:13:26Z")

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IIRC, the Ignition setting only takes one address. Use `0.0.0.0` to listen on all networks. Use a firewall to block any undesirable traffic.

You will probably want to also give the PC a **name** for use in certificates, and arrange for DNS on each network to yield the right IP address on that side. (AKA "localizing queries" in `dnsmasq` or similar DNS caches.)

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<div class="post-metadata">

**Author:** ![Ian\_McArdle](https://avatars.discourse-cdn.com/v4/letter/i/f1d935/32.png) [@Ian\_McArdle](https://forum.inductiveautomation.com/u/Ian_McArdle)\
**Post date:** [December 16, 2024, 4:10pm UTC](https://forum.inductiveautomation.com/t/opc-ua-server-and-two-nics/99880/4 "2024-12-16T16:10:39Z")

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Thanks for the quick replies!

Given that the OPC-UA server setting is labelled "Bind Address **es**", I had assumed that I need to put every IP address (or host name) that I want to use as a client in that field. I had a comma separated list of about half a dozen addresses. Interestingly, that list included the 0.0.0.0 address that you mentioned - but it did not work until I removed all of the other addresses leaving only that one and restarted the OPC-UA module.

I will also check the DNS server situation.

Thanks so much for solving the puzzle!