I'm experiencing some odd behaviour from Firefox when there is a connection lag:

- Pages showing as html/xml source code rather than as web pages
- Error messages saying that I cant load the page/have a connection issue that refer to a page that I loaded a long time ag or opened in another tab.
- The browser not recognising a php or html page and instead opening the same dialog as if I had chosen "save link as" (this last happened 30 seconds ago browsing this forum).

I've not been able to find anything about those issues on the firefox forums, (there has been hints at Avast Antivirus' internet shield causing timeouts, but I have switched that feature off), so I wonder if you guys have experienced any of this crap or have any speculation as to what it could be.
 
No clue, but for starters, which version do you have? I'm using Firefox 2.0.0.11. None of the problems mentioned above. Are you sure the problem is not in the connection itself?
 
2.0.0.11, but I've encountered this with every version since 2.0.0.8 at least.

It's probably not a problem with my connection. It's not completely reproducible, but I usually get it with slower web servers. I strongly suspect that it is caused by some Firewall (Sunbelt personal firewall)/AV compatibility issue that triggers illogical behaviour from FF.

We occasionally connect another PC that use Kaspersky internet security (AV with integrated firewall) using the same connection, and that machine doesnt have those issues at all.
 
It's probably not a problem with my connection. It's not completely reproducible, but I usually get it with slower web servers. I strongly suspect that it is caused by some Firewall (Sunbelt personal firewall)/AV compatibility issue that triggers illogical behaviour from FF.
I had a similar problem a week ago, but in my case it was the cable modem. It was 7 years old and just died. When it comes to connecting your pc to the net, you have to eliminate every step -> routers, networkcard, modem, software on the pc, ...
 
As I said it's not 100% reproducible. The last error occured with this forum. I've had the others with my daily targets www.svenskafans.com/fotboll/hbk (which is a fairly fast site with limited server load) and more often with the often overburdened and slow forum.paradoxplaza.com.

I'm fairly sure that I can remove the cable modem from the list of possible culprits due to the other PC working:)

As for software I've had the issue with a Kaspersky AV/Sunbelt firewall combo as well in the past (Avast is installed because we didnt renew that Kaspersky license a month ago).

What I find most funny is that Firefox give 404 errors that claim the program tried to load some website that I've visited in the past rather than the one I actually tried to load. I havent found any other references to that particular error.
 
Another funny one, from when I tried to press the "next" button in yahoo mail:

Request header field is missing colon separator.

POST /ym/ShowLetter?Search=&Idx=0&YY=43441&y5beta=yes&y5beta=yes&order=down&sort=date&pos=0&view=a&head=b HTTP/1.1

Please check the URL for proper spelling and capitalization. If you're having trouble locating a destination on Yahoo!, try visiting the Yahoo! home page or look through a list of Yahoo!'s online services. Also, you may find what you're looking for if you try searching below.
 
Seems like it is the firewall: http://forums.mozillazine.org/viewtopic.php?p=3017094 describes exactly the same problem, and I dont suffer the symptoms when the firewall is switched off (nor on the other PC that uses a different firewall).

EDIT: That sunbelt personal firewall is the culprit seems more or less confirmed. Almost one hour with Comodo hasnt seen any of the issues mentioned.
 
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