The sparkly shiny, new Enterprise Vault Search available with Enterprise Vault 11.0.0 was implemented for a known path on the server, that being \EnterpriseVault\Search\.
That's all fine and lovely for all your internal, direct clients. But say you want to publish it via Forefront TMG or something similar. Even better, you have yourself a shiny production EV environment and a not so shiny but nonetheless much loved lab EV environment to test out all those funky policy settings, or upgrades and the like. And you want to publish both of those via the same TMG setup, so users can get to the important stuff and you can test stuff out with your lab.
Easily done: one listener, a couple of publishing rules capturing different paths to send the traffic over to the correct EV system, and Bob is very much your uncle. Isn't he?
In my simple lab setup, you can see I'm publishing two EV servers using the same listener with the internal /EnterpriseVault/Search/* path mapped to different external paths.
So clients can get to my 11.0.0 system using https://tmg.cft.local/asg1100search and to my 11.0.1 system using https://tmg.cft.local/asg1101search. Like this:
Huh? That's not right!
As it turns out; Enterprise Vault Search will still try to load things from \EnterpriseVault\Search\, and of course TMG hasn't published that path.
The trick is to add a link translation rule so that TMG ensures the links inside of Enterprise Vault Search point to the path TMG publishes, rather than the internal path.
Hello search.
There is one other thing I should mention here as we're discussing setting up Enterprise Vault Search and TMG, although I'm sure you'll have spotted it in the Installing & Configuring guide already. If you're using forms based authentication, then you'll need to tweak the Web.Config file for Enterprise Vault Search as per this article.