I have two web servers on my computer (name mr2): one on the default port 80, one on the port 81. If I type in the URL bar (idem if the link is in an HTML document) http://mr2, I have the page on the first server (OK). I then I type http://mr2:81, it stay on the page on port 80, even if I do a reload. In fact, it seems to complemtely ignore the port as I can type http://mr2:82 (does not exists) and it continue to give me the same page.
Read the bug reporting guidelines http://www.mozilla.org/quality/bug-writing-guidelines.html to learn how to write bug reports that get bugs fixed. this bug is missing essential things like a build id, and a url to test. in fact, it's quite likely that we fixed this problem this week, but you neglected to include a build id.
For what I understood, it's bug 51237
it actually a dupe of bug 51237- which was fixed before this was written so I don't feel so bad marking this VERIFIED Invalid even though it could just be a dupe.