Why am I unable to connect to a Splunk server from a different domain?

[nk-1]

Trying to connect to a Splunk 6.5 server in domain D1 from domain D2.

Within domain D1,
works: http://hostnameXXX.org:8000

From domain D2,

1. fails: http://hostnameXXX.org:8000
   ("The connection was reset. The connection to the server was reset while the page was loading.")

2. works: http://hostnameXXX.org:80
   (MS IIS home page)

3. works: telnet hostnameXXX.org 8000
   (so port is open and visible)

What could be the problem?
Any other port that needs to be opened?

[woodcock]

Disable the firewall running on the host and see if it works then.

[gjanders]

Do you have a proxy server configured within your browser? A proxy might block the connection from your browser if it's not in some kind of bypass list...?

Perhaps test with firefox/chrome or change your browser settings to disable the proxy, this should force your browser to act the same as telnet (direct connection).

[nk-1]

I configured Splunk to use port 8080, and the Splunk web-interface works fine now from the other domain.
Something about port 8000...