Transparent proxy servers

[TheRoDent]

I'll bet a lot of you might not have known this, but Telkom's ADSL network intercepts all HTTP traffic on port 80, and relays this through a transparent proxy.

These transparent proxies implement a throttle limit, of around 10kb/sec for each HTTP connection.

When downloading a file over HTTP, the maximum rate I've seen is around 10-15kb/sec

However, when using a download manager such as flashget, which uses MULTIPLE http connections and "swarm" downloads the file in various pieces, the total transfer rate can go up to the maximum of your line, i.e. around 50kb/s.

This is a fact. Go test it. Download something using a single HTTP connection in your browser, and you'll get a measly 10kb or so per second.

Download another file using a swarming download manager and you will get your full 50kb/s throughput.

This is one thing that seriously peeves me because it means that during normal browsing, the maximum http transfer rate I'll get to any site is about 10-20kb/sec.

Would telkom care to explain this to us?

 

[TheRoDent]

Some additional information. The reason why I know a transparent cache/proxy is in use: Try to access a website that is down.

Instead of getting the usual error, you will get an error message from the transparent proxy informing you that the target host is down.

In fact, telnetting to the "down" host on port 80, still yields a connection, and a get for a page on the site that is down, yields the transparent proxy's error message.

 

[ASnogarD]

I am the last person to jump to Telkoms defence but uncapped I have got in excess of 40 k/sec downloads,sustained without any download manger or accelerator. I was under the impression Telkom encourages HTTP traffic at the expence of P2P or IRC or gaming.

Quiet frankly I am happy with ADSL uncapped...just this bless lasts about 5 days []

 

[TheRoDent]

Also, the HTTP headers from a get from e.g. google.com reveals the transparent cache and it's interference with the http headers.

e.g.

telnet www.google.com 80
GET / HTTP/1.0

HTTP/1.0 200 OK
Date: Wed, 06 Aug 2003 15:28:30 GMT
Content-Length: 3273
Content-Type: text/html
Cache-Control: private
Set-Cookie: PREF=ID=12fb979605867624:TM=1060183710:LM=1060183710:S=lshzBF5CWexFknFe; expires=Sun, 17-Jan-2038 19:14:07 GMT; path=/; domain=.google.com
Server: GWS/2.1
Via: 1.1 ndf-cache1 (NetCache NetApp/5.3.1R3D2)

^^^^^

The "Via: 1.1 ndf-cache1 (NetCache" header is indicative of a transparent proxy announcing it's interference in the HTTP stream.

I don't mind so much them using transparent caches. What I DO mind is the 10kb/sec HTTP connection cap they've implemented.

I want to do HTTP transfers at the full 50kb/sec my line is capable of. Not some abitrary limit they decided on...

 

[pdos]

Yes, I have noticed exactly the same thing with downloads and I agree with your conclusions.

I think it is downright immoral that unkown, secret conditions are imposed on us.
When entering into this service we are forming a contractual relationship with Telkom. And we have the simple right to know the full details of that contract.