Application Layer Packet Shaping on Linux
sommere writes "We have added application layer (layer-7) filtering to Linux. That means that you can set up your linux-router/linux-switch to prioritize mail over the web over kazaa or gnutella regardless of what port each program is using. Colleges have been paying thousands of dollars for packet shapers to prioritize their networks, now you can do it for free. Get your kernel patch at l7-filter.sourceforge.net."
This really helps networks that have smaller circuits and lots of clients doing various tasks on them. Not such a big help for a home user but great for corporations.
It's looking more and more like commodity linux boxen, with the right software, can do what your average pricey cisco box is renowned for.
If you can't beat them, arrange to have them beaten. -George Carlin
In one hand, >I can prioritize what I want how I want. And it was good.
In the other hand, my ISP may downgrade my Quake performance or my school may block telnetting to my home box completely (no matter which port I put the demon on). And this was bad.
The idea is good but I'm worried it will be heavily abused and that worries me. In the other hand, it may mean a neat security tool...
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For those of us practicing for our CCNA exams... packets are at layer 3, its known as data at layer 7.
FLR
...except that ALTQ handles layer 3 of the protocol stack, not layer 7. ALTQ is incapable of recognizing the difference between an HTTP session and an SSH session if such a session were established on an arbitrary port.
ALTQ relies on the fact that well-known services are traditionally bound to assigned ports. The new layer 7 code allows the administrator to eliminate such an assumption.
Yep. Fragment your packets so much the router won't be able to recognise them. The admin will thank you, you've just downgraded your own performance yourself so much that no traffic shapers are needed. (Note: More packets=More overhead=Less data in one frame, plus what about incoming packets? How do you tell the remote host to fragment them?)
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