address is configured on a interface. This is useful for routers with
dynamic interfaces. It is now possible to say:
0100 allow tcp from any to any established
0200 skipto 1000 tcp from any to any
0300 allow ip from any to any
1000 allow tcp from 1.2.3.4 to me 22
1010 deny tcp from any to me 22
1020 allow tcp from any to any
and not have to worry about the behaviour if dynamic interfaces configure
new IP numbers later on.
The check is semi expensive (traverses the interface address list)
so it should be protected as in the above example if high performance
is a requirement.
It also squashes 99% of packet kiddie synflood orgies. For example, to
rate syn packets without MSS,
ipfw pipe 10 config 56Kbit/s queue 10Packets
ipfw add pipe 10 tcp from any to any in setup tcpoptions !mss
Submitted by: Richard A. Steenbergen <ras@e-gerbil.net>
Packets that match a tee rule should not be immediately accepted,
but should continue going through the rule list. This may be fixed
in a later version.
I hope to fix this soon in a separate commit.
using syslog(3) (log(9)) for its various purposes! This long-awaited
change also includes such nice things as:
* macros expanding into _two_ comma-delimited arguments!
* snprintf!
* more snprintf!
* linting and criticism by more people than you can shake a stick at!
* a slightly more uniform message style than before!
and last but not least
* no less than 5 rewrites!
Reviewed by: committers
_or_ you may specify "log logamount number" to set logging specifically
the rule.
In addition, "ipfw resetlog" has been added, which will reset the
logging counters on any/all rule(s). ipfw resetlog does not affect
the packet/byte counters (as ipfw reset does), and is the only "set"
command that can be run at securelevel >= 3.
This should address complaints about not being able to set logging
amounts, not being able to restart logging at a high securelevel,
and not being able to just reset logging without resetting all of the
counters in a rule.
This allows for more flexible ipfw configuration files using
`variables' to describe frequently used items in the file, like the
local IP address(es), interface names etc. Both m4 and cpp are useful
and supported; with m4 being a little more unusual to the common C
programmer, things like automatic rule numbering can be achieved
fairly easy.
While i was at it, i've also untangled some of the ugly style inside
main(), and fixed a bug or two (like not being able to use blank lines
when running with -q).
A typical call with preprocessor invocation looks like
ipfw -p m4 -Dhostname=$(hostname) /etc/fwrules
Someone should probably add support for this feature to /etc/rc.firewall.
Any packet that can be matched by a ipfw rule can be redirected
transparently to another port or machine. Redirection to another port
mostly makes sense with tcp, where a session can be set up
between a proxy and an unsuspecting client. Redirection to another machine
requires that the other machine also be expecting to receive the forwarded
packets, as their headers will not have been modified.
/sbin/ipfw must be recompiled!!!
Reviewed by: Peter Wemm <peter@freebsd.org>
Submitted by: Chrisy Luke <chrisy@flix.net>
offset is non-zero:
- Do not match fragmented packets if the rule specifies a port or
TCP flags
- Match fragmented packets if the rule does not specify a port and
TCP flags
Since ipfw cannot examine port numbers or TCP flags for such packets,
it is now illegal to specify the 'frag' option with either ports or
tcpflags. Both kernel and ipfw userland utility will reject rules
containing a combination of these options.
BEWARE: packets that were previously passed may now be rejected, and
vice versa.
Reviewed by: Archie Cobbs <archie@whistle.com>
