279707 - Mozilla/Firefox try to access local port before opening remote website; results in connection refused

Status: VERIFIED DUPLICATE of bug 100154

(Core :: Networking, defect)

Description

[Dave G.]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041111 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; WIndows NT 5.0; en-US; rv1.8a6) Gecko/20050111

(System is Windows 2000/SP4, with ZoneAlarm firewall installed and running.)

When starting up Mozilla or Firefox, firewall reports attempt to access local
port in the low 1000s (e.g. 127.0.0.1:1461). Any attempt to access  NON-local
websites (i.e. anything not on my LAN) results in a connection refused error dialog.

Problem was first noticed when installing FireFox 1.0 on a fresh Windows 2000
system. Allowing the access to the local port resulted in FireFox hanging--app
window never appeared, no listing in Task list, but the process was still listed
under process list. Denying access to the local port allowed FireFox to open,
but no websites outside the local net could be reached--connection refused
dialog instead.

Applying Win2K Service Pack 4 ameliorated the problem slightly--allowing access
to the local port resulted in FireFox actually coming up, AND being able to
access websites. However, denying access to the local port still results in
connection refused.

I downloaded Mozilla as well to test this--same problem.

Reproducible: Always

Steps to Reproduce:
1. On a Win2K system, with a firewall installed and set to prompt for access,
open Mozilla
2. When the firewall prompts to allow access to 127.0.0.1 on some port (it's
been slowly counting up from 1025, I think, and is now around 1520), deny the access
3. Enter a non-local website in the URL bar if Mozilla isn't set to load a
non-local homepage already
4. If the firewall prompts to allow access to the DNS server, allow it.

Actual Results:  
Dialog pops up showing "Connection was refused when attempting to contact <website>"

Expected Results:  
Firefox/Mozilla shouldn't be trying to access local ports for remote webpage?
Firefox/Mozilla should display the website.

Entered bug under Mozilla because that's the program for which I downloaded the
latest build to verify the bug still existed.
Tested on FireFox 1.0, Mozilla 1.7.5, and Mozilla 1.8a6.
Fresh install of Windows 2000 with SP4 (Build 2195 SP4)
ZoneAlarm 5.0.590.043
Local network is 192.168.0.0/24; internet connection is via CoyoteLinux firewall
masquerading a cablemodem connection

Comment 1

[OstGote!]

Mozilla needs on the local side a TCP port to establish a connection to a remote
server/proxy. 

mozilla.exe 127.0.0.1:1052 (local) --> IP-Address:port (remote)

You should configure your firewall settings better. Access to
localhost/127.0.0.1 is allowed from all local programs/localhost. I guess this
bug is INVALID (not a Mozilla problem).

Comment 2

[Christian :Biesinger (don't email me, ping me on IRC)]

firstly, blocking localhost->localhost connects is rather pointless

that said... I think mozilla is supposed to handle this case... (the comment at
http://lxr.mozilla.org/seamonkey/source/netwerk/base/src/nsSocketTransportService2.cpp#376
seems to say so)

Comment 3

[Dave G.]

Thanks for the feedback--I realize local->local isn't usually a problem, but I
never saw this with earlier versions, nor indeed any other program accessing a
(to me strange) local port, and couldn't find ANY information online--even on
the newsgroups. 

Just for my personal education, what IS mozilla/firefox trying to access in that
range? I understand the DNS port, and the http port, but what's at
localhost:(1025..11??) that moz/ff needs to work?

Comment 4

[Christian :Biesinger (don't email me, ping me on IRC)]

the port numbers are random... mozilla just does some communication between two
threads over that connection, it's a form of IPC.

Comment 5

[Darin Fisher]

bug 264268 is about removing the loopback socket pair to avoid these lame
firewall warnings.  this bug may also very well be a dupe.

Comment 6

[Matthias Versen [:Matti]]

*** This bug has been marked as a duplicate of 100154 ***

Comment 7

[benc]

V/dupe.