# Ignition OPC UA fails after upgrade **URL:** \ **Category:** Ignition\ **Tags:** ignition79\ **Created:** [August 29, 2018, 2:11am UTC](https://forum.inductiveautomation.com/t/ignition-opc-ua-fails-after-upgrade/19437 "2018-08-29T02:11:39Z")\ **Posts on this page:** 1\ **Showing post:** 12
**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:** [August 29, 2018, 12:40pm UTC](https://forum.inductiveautomation.com/t/ignition-opc-ua-fails-after-upgrade/19437/12 "2018-08-29T12:40:06Z")
One of the things that happens when the session is activated is the server ends up doing a call to `InetAddress.getLocalHost().getHostAddress()` (for reasons that don’t make any sense; this call should be removed). We’ve seen [DNS lookups take a long time on Linux in the past](http://forum.inductiveautomation.com/t/starting-ignition-gateway-takes-almost-10-minutes-when-not-connected-to-internet/17588/8). The behavior you’re seeing makes it seem like the lookup succeeds quickly when you’re assigned to the off-subnet test IP, but takes a long time with the correct IP. Try adding your IP address and hostname to `/etc/hosts` and see if it works. --- _[View the full topic](https://forum.inductiveautomation.com/t/ignition-opc-ua-fails-after-upgrade/19437)._