ng_ipfw(4) [debian man page]

NG_IPFW(4)						   BSD Kernel Interfaces Manual 						NG_IPFW(4)

NAME

     ng_ipfw -- interface between netgraph and IP firewall

SYNOPSIS

     #include <netgraph/ng_ipfw.h>

DESCRIPTION

     The ipfw node implements interface between ipfw(4) and netgraph(4) subsystems.

HOOKS

     The ipfw node supports an arbitrary number of hooks, which must be named using only numeric characters.

OPERATION

     Once the ng_ipfw module is loaded into the kernel, a single node named ipfw is automatically created.  No more ipfw nodes can be created.
     Once destroyed, the only way to recreate the node is to reload the ng_ipfw module.

     Packets can be injected into netgraph(4) using either the netgraph or ngtee commands of the ipfw(8) utility.  These commands require a
     numeric cookie to be supplied as an argument.  Packets are sent out of the hook whose name equals the cookie value.  If no hook matches,
     packets are discarded.  Packets injected via the netgraph command are tagged with struct ng_ipfw_tag.  This tag contains information that
     helps the packet to re-enter ipfw(4) processing, should the packet come back from netgraph(4) to ipfw(4).

	 struct ng_ipfw_tag {
		 struct m_tag	 mt;		 /* tag header */
		 struct ip_fw	 *rule; 	 /* matching rule */
		 uint32_t	 rule_id;	 /* matching rule id */
		 uint32_t	 chain_id;	 /* ruleset id */
		 struct ifnet	 *ifp;		 /* interface, for ip_output */
		 int		 dir;		 /* packet direction */
	 #define NG_IPFW_OUT	 0
	 #define NG_IPFW_IN	 1
	 };

     Packets received by a node from netgraph(4) must be tagged with struct ng_ipfw_tag tag.  Packets re-enter IP firewall processing at the next
     rule.  If no tag is supplied, packets are discarded.

CONTROL MESSAGES

     This node type supports only the generic control messages.

SHUTDOWN

     This node shuts down upon receipt of a NGM_SHUTDOWN control message.  Do not do this, since the new ipfw node can only be created by reload-
     ing the ng_ipfw module.

SEE ALSO

     ipfw(4), netgraph(4), ipfw(8), mbuf_tags(9)

HISTORY

     The ipfw node type was implemented in FreeBSD 6.0.

AUTHORS

     The ipfw node was written by Gleb Smirnoff <glebius@FreeBSD.org>.

BSD
								   June 10, 2009							       BSD

Check Out this Related Man Page

IPFW(4) 						   BSD Kernel Interfaces Manual 						   IPFW(4)

NAME

     ipfw -- IP packet filter and traffic accounting

SYNOPSIS

     To compile ipfw into the kernel, place the following option in the kernel configuration file:

	   options IPFIREWALL

     Other kernel options related to ipfw which may also be useful are:

	   options IPFIREWALL_DEFAULT_TO_ACCEPT
	   options IPFIREWALL_FORWARD
	   options IPFIREWALL_VERBOSE
	   options IPFIREWALL_VERBOSE_LIMIT=100

     To load ipfw as a module at boot time, add the following line into the loader.conf(5) file:

	   ipfw_load="YES"

DESCRIPTION

     The ipfw system facility allows filtering, redirecting, and other operations on IP packets travelling through network interfaces.

     The default behavior of ipfw is to block all incoming and outgoing traffic.  This behavior can be modified, to allow all traffic through the
     ipfw firewall by default, by enabling the IPFIREWALL_DEFAULT_TO_ACCEPT kernel option.  This option may be useful when configuring ipfw for
     the first time.  If the default ipfw behavior is to allow everything, it is easier to cope with firewall-tuning mistakes which may acciden-
     tally block all traffic.

     To enable logging of packets passing through ipfw, enable the IPFIREWALL_VERBOSE kernel option.  The IPFIREWALL_VERBOSE_LIMIT option will
     prevent syslogd(8) from flooding system logs or causing local Denial of Service.  This option may be set to the number of packets which will
     be logged on a per-entry basis before the entry is rate-limited.

     Policy routing and transparent forwarding features of ipfw can be enabled by IPFIREWALL_FORWARD kernel option.

     The user interface for ipfw is implemented by the ipfw(8) utility, so please refer to the ipfw(8) manpage for a complete description of the
     ipfw capabilities and how to use it.

SEE ALSO

     setsockopt(2), divert(4), ip(4), ipfw(8), sysctl(8), syslogd(8), pfil(9)

BSD
								 September 1, 2006							       BSD

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ng_ipfw(4) [debian man page]

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