Ignition 8.1 gateway sat in the server room, KEPServerEX 6.x on a box out in the plant, OPC UA between the two. From my laptop on the plant network the endpoint opc.tcp://kep01:49320 connects fine and the tags browse.
From the gateway, IT insist on the full name, opc. removed link , and that connection sits at Faulted with BadCertificateHostNameInvalid in the gateway log.
I turned the Windows firewall off on the KEP box for a few minutes, no change there, and I trusted the server certificate in the gateway's OPC UA Security tab, where it now shows as trusted, and it still faults. I pinged kep01.plant.local from the gateway too and it resolves to the right IP, so DNS is doing its bit.
Why would the same server take one name and not the other? Same certificate either way. Has the KEP box only got kep01 in its certificate, and if it has, is that something I fix on the KEP side or on the gateway?
Could be the certificate rather than anything on the network. On the KEP box open the OPC UA Configuration Manager, Instance Certificates, select the server certificate, View. What's in the Subject Alternative Name list? Post the DNS names and the IPs.