Filtering: MSIE gets filtered URL's in backlog
Hi there,
I've recently switched from Squid to the Java webproxy and so far I really like what I see. However the web filtering is giving me some strange problems on MS Internet Explorer.
For example, take the http://www.planet-source-code.com website. You'll notice that one of the commonly used ad sources is http://ads2.exhedra.com/ads/. So I setup a filter which contains this URL (amongst some others) and told the server to send a text/html file as response. This is a plain HTML file with a grey background and black textfont and basicly says that the contents is blocked.
To my surprise I don't see this HTML file appear on Mozilla, I simply see nothing of the advertisement anymore. On MSIE however I get a "forbidden" response in all sections which normally would be filled with advertising. Its ugly, nothing serious. Its becoming odd when I look at the "backlog" and see all the spam url's appear. Whenever I click "back" in the browser one of the sections on the webpage turns to my grey block message. And only when all 4 - 5 sections have been "backed out" this way does the user get to go to the previous page.
So basicly; the complaint I now get from my users is that they're unable to press "back" in order to go back to the previous webpage.
Can someone shed some light on what might be happening here? Because the contents are blocked and is all part of a single webpage I don't understand why the proxy server is seemingly feeding the clients with all those several extra URL's. It makes no sense to me...
Next I tried the content url rewriting hoping that I could make the server change the 'ads' URL to a local URL. This gives me the exact same results. I'm a little bit at a loss here.
[1762 byte] By [
Lion-O] at [2007-11-26 9:18:28]
# 1
Whenever you talk to a webdesigner who knows what he's doing (meaning; knows of the existance of web standards and knows about different browsers) you're bound to hear horror stories about MSIE totally violating those standards. Take a certain, W3C compliant webpage which looks good in both Mozilla, Firefox (basicly the same) and Opera and chances are still high that it looks awfull in MSIE.
This whole deal is sort of taking that complaint up to a whole new level. As I denoted in my previous message I basicly blocked all of http://ads2.exhedra.com/ads/ and replaced the contents. Now, I'm no webdeveloper so this is but a theory but it the URL's which pose a problem all create "virtual frames". Basicly its a table getting filled in but it seems as if some parts of the table is generated dynamicly. And because MSIE seemingly has a huge problem with it it starts treating the empty "frame" contents as seperate pages, with the above behaviour as a result.
The solution turns out to be URL rewriting after all. The reason why it didn't work for me earlier was that I didn't setup the proper rules. Whenever you specificly remove some "ad script" you'll gain a lot more success. So, instead of trying to rewrite http://ads2.exhedra.com/ads/* I basicly went for http://ads2.exhedra.com/ads/ ShowAd.asp which has a lot more results. At first I tried this at home with good results, now the company part has been fixed as well. Instead of sending people the above greyish HTML I'm now sending a grey plaster picture from a local webserver. Works excellent, basicly the same approach I used on Squid. So, for the record, an obj.conf snipplet:
<Object ppath="http://.*">
Output fn="insert-filter" filter="content-rewrite" from="http://ads2.exhedra.com
/ads/ShowAd.Asp" to="http://www.intranet.lan/siteimages/backgrounds/plaster.jpg"
type="*"
...
</Object>
And after that you'll have no problems what so ever with that advertisement spam on both Mozzie (or other browsers) and MSIE :-)
If there are still people wondering about this product then I can only assure them that it fully blows Squid out of the water where functionality is concerned. Even the administrative part is to my opinion a lot better, but thats all but personal taste. Right now I have a lot of people telling me how all of a sudden their posts on forums aren't as agressively throttled anymore as it used to. It seems that Squid didn't really manage to keep full track on who was doing what, resulting sometimes in a situation where co-worker A would post something and co-worker B would end up getting throttled. That too is a thing of the past now.
LionO at 2007-7-6 23:47:36 >
