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Move the discussion of how many times a packet will pass through

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ipfirewall(4) to the IMPLEMENTATION NOTES section because it
considers kernel internals and may confuse newbies if placed
at the very beginning of the manpage (where it used to be previously.)

Not objected by:	luigi
This commit is contained in:
Yaroslav Tykhiy 2002-01-02 20:48:21 +00:00
parent 2ba633961e
commit c1201321e4
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=88833
1 changed files with 18 additions and 20 deletions
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38
sbin/ipfw/ipfw.8
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@ -62,27 +62,9 @@ and the
traffic shaper in
.Fx .
.Pp
Each incoming or outgoing packet is passed through the
.Nm
rules.
The number of times a packet is processed by
.Nm
varies \(em basically,
.Nm
is invoked every time the kernel functions
.Fn ip_input ,
.Fn ip_output
and
.Fn bdg_forward
are invoked.
This means that packets are processed once for connections having
only one endpoint on the local host, twice for connections with
both endpoints on the local host, or for packet routed by the host
(acting as a gateway), and once for packets bridged by the host
(acting as a bridge).
.Pp
A firewall configuration is made of a list of numbered rules,
which is scanned for each packet until a match is found and
which is scanned for each incoming or outgoing IP packet
until a match is found and
the relevant action is performed.
Depending on the action and certain system settings, packets
can be reinjected into the firewall at the rule after the
@ -1341,6 +1323,22 @@ on a net with per-host limits, rather than per-network limits:
.Dl "ipfw add pipe 2 ip from any to 192.168.2.0/24 in"
.Dl "ipfw pipe 1 config mask src-ip 0x000000ff bw 200Kbit/s queue 20Kbytes"
.Dl "ipfw pipe 2 config mask dst-ip 0x000000ff bw 200Kbit/s queue 20Kbytes"
.Sh IMPLEMENTATION NOTES
The number of times a packet is processed by
.Nm
varies \(em basically,
.Nm
is invoked every time the kernel functions
.Fn ip_input ,
.Fn ip_output
and
.Fn bdg_forward
are invoked.
This means that packets are processed once for connections having
only one endpoint on the local host, twice for connections with
both endpoints on the local host, or for packet routed by the host
(acting as a gateway), and once for packets bridged by the host
(acting as a bridge).
.Sh SEE ALSO
.Xr cpp 1 ,
.Xr m4 1 ,