Blocking of domain strings in iptables
bortzmeyer at nic.fr
Sat Feb 8 17:16:45 UTC 2014
On Sat, Feb 08, 2014 at 12:34:45AM -0800,
Jonathan Lassoff <jof at thejof.com> wrote
a message of 88 lines which said:
> This is going to be tricky to do, as DNS packets don't necessarily
> contain entire query values or FQDNs as complete strings due to
> packet label compression
Apprently, the OP wanted to match the *question* in a *query* and
these are never compressed (they could, in theory, but are not).
> You can use those u32 module matches to find some known-bad packets
> if they're sufficiently unique, but it simply lacks enough logic to
> fully parse DNS queries.
u32's language is not Turing-complete but It is sufficient in the case
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