Nmap Development: Re: [updated patch] fragment scan got broken between 3.50 and 3.75

[Martin Mačok <martin.macok () underground cz>]

On Sun, Jan 30, 2005 at 02:35:18PM +0300, Andrey A. Tutolmin wrote:

> MM> Can FreeBSD send tiny fragments (mtu=20+8)? Could you check it with
> MM> hping2 or some other tool/lib?
> I've just read through man on ipfw
> and found out that:
>          There is one kind of packet that the firewall will always discard,
>          that is a TCP packet's fragment with a fragment offset of one.  This
>          is a valid packet, but it only has one use, to try to circumvent
>          firewalls.  When logging is enabled, these packets are reported as
>          being dropped by rule -1.
> So that is why I've been getting this permission denied messages.
> I turned off firewall complitely:
> sysctl -w net.inet.ip.fw.enable=0
Thank you for bringing this issue up.

> Everything works fine right now.
Good news!

Martin Mačok
ICT Security Consultant

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