Windows XP: IPv6 web browsing blocked by McAfee Virusscan ..

This is a strange thing with IPv6 web browsing on WinXP, probably caused by
McAfee Virusscan version 9.0, and certainly solved by de-installing McAfee
Virusscan.

All my Windows XP machines (SP2) have native IPv6 connectivity: ping6, ssh,
and telnet all work inside and outside the LAN.

However, when using a webbrowser (Firefox, IE, Opera), none of the WinXP
machines can connect to IPv6-websites over IPv6. In Firefox, after
"connecting to ...", I get a popup saying "connection refused". The same
happens when using IE and Opera.

Now something even more strange: telnet-ing to port 80 of those IPv6-enabled
sites, gives correct connectivity over IPv6...!

The IPv6 connectivity is native, no tunneling (no 6over4, no 6to4, no
teredo). No firewall is turned on on the XP machines nor the LAN.
Re-installing the IPv6 stack didn't solve the problem. IPv6 web browsing has
worked in the past, and stopped some months, probably after some upgrade
(SP2? Virusscanner?)

The Linux systems on the same LAN have no problems: IPv6 with all protocols
works great.

I couldn't find a reason, so I posted the problem in xs4all.general, subject
"IPv6 en WinXP-SP2: wel ping6 en ssh, geen http-verbinding.", with no
result. Until someone (Hugo) posted a followup: he told he had experienced
the same, and it was caused by McAfee *Virusscan* (not a firewall). After
de-installing McAfee Virusscan, the problem was solved. Just de-activating
McAfee Virusscan didn't solve it.

I tried this, and it worked for me: I can now browse to IPv6 websites again.
(I must say it looked like to took 10 minutes after the de-install before
the IPv6 websites were reachable, but that could be a caching thing)

No information on IPv6 on mcafee.com nor mcafeehelp.com.

So far my FYI.

Now my questions:
1) If pure telnet-ing to port 80 over IPv6 works great, but higher level
normal web browsing over IPv6 doesn't, there must be a difference. Do
webbrowsers on Windows use some common Windows HTTP function/DLL?
2) How can McAfee Virusscan block the IPv6 HTTP web browsing *at all*? Does
a virusscanner has the possibility to hook itself into that supposed Windows
HTTP-getting function / DLL?
3) Is the problem caused by Microsoft Windows or McAfee Virusscan? In other
words: who should solve this?
4) Does anybody know a workaround where I can have full IPv6 connectivity
and virus protection at the same time? My ISP xs4all only supplies McAfee
virusscanner.


De Kameel

Hugo wrote:

> By the way: how do you do that: your (and mine) provider xs4all gives
> you only the possibility of ipv6-tunneling, and you write that your
> IPv6-connectivity is native, without tunneling?

I posted that the WinXP machines have native IPv6, because the tunneling is
done somewhere else by a router. The WinXP can't know that.

De Kameel