Re: [PATCH] More Documentation/Changelog fixes

Alan Cox (alan@lxorguk.ukuu.org.uk)
Mon, 21 Sep 1998 17:18:19 +0100 (BST)


> 3) CONFIG_IP_ALWAYS_DEFRAG is still a good idea for packet filtering
> firewalls, but second and furthur fragments are no longer accepted
> by default.

Thats not a good idea. We send UDP datagrams in reverse fragment order.
The cisco pix does broken filtering by waiting for the misnamed "first"
fragment now days and several folk have a choice of running
old versions or changing product.

It also doesn't work on dual entry point networks where fragments may
pass down different paths and firewalls. Something required for a serious
ISP set up where even a hardware failure of a firewall host taking out
the network is unacceptable.

I assume the "first fragment first" is at least configurable so everyone
can turn it off again

Alan

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