table of contents
IPFW(4) | Device Drivers Manual | IPFW(4) |
NAME¶
ipfw
—
SYNOPSIS¶
To compile the driver into the kernel, place the following option in the kernel configuration file:options IPFIREWALL
Other related kernel options which may also be useful are:
options
IPFIREWALL_DEFAULT_TO_ACCEPT
options IPFIREWALL_VERBOSE
options IPFIREWALL_VERBOSE_LIMIT=100
To load the driver as a module at boot time, add the following line into the loader.conf(5) file:
ipfw_load="YES"
DESCRIPTION¶
Theipfw
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 accidentally 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.
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)October 25, 2012 | Linux 4.19.0-10-amd64 |