Editing Firewall

{{welcome}}
==Introduction==
IPFW or ipfirewall is an internet-protocol-firewall  written for FreeBSD. 
The ipfw system facility allows filtering, redirecting, and other operations on IP packets travelling through network interfaces.
A firewall	configuration, or ruleset, is made of a	list of	rules numbered    from 1 to 65535.  Packets are passed to the firewall from a number	of     different places in the protocol stack (depending on the source and destination of the packet, it	is possible for	the firewall to	be invoked     multiple times on the same	packet).  The packet passed to the firewall is     compared against each of the rules	in the ruleset,	in rule-number order     (multiple rules with the same number are permitted, in which case they     are processed in order of insertion).  When a match is found, the action     corresponding to the matching rule	is performed.



==IPFW on GhostBSD==

On GhostBSD ipfw is managed by [[OpenRC]]. 

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|style="text-align:center;padding: 10px" | [[File:Dialog-warning.png|35px|link=]] '''Attention:  Please do not use FreeBSD firewall guidance on the FreeBSD handbook.'''
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IPFW is already setup to default: [[/boot/defaults/loader.conf#Set ipfw to default accept|Set ipfw to default accept]]<br/>
If you run <code>[[Rc-update|rc-update]]</code> it shows all running services, ipfw included. 
 

[[OpenRC]] manages how ipfw (/etc/[[Init.d|init.d]]/ipfw) configuration is initialized. <br/>

The old way defined by TrueOS allows you to define the firewall rules via a /etc/ipfw.conf file.  You have to create that file as it does not exist by default.<br/>

However, OpenRC (main branch) defines the firewall rules within the '''/etc/ipfw.rules''' file itself.<br/>
If the file does not exist on GhostBSD you have to create it. 

See examples: 
* [https://gist.github.com/nileshgr/5990712 Nilesh on Github]
* [https://unixguide.net/freebsd/fbsd_installguide71/06.09.4-IPFW_Rule_Sets.htm unixguide]
* [https://sirtoffski.github.io/docs/freebsd-ipfw/ ipfw.rules]

See: [https://github.com/OpenRC/openrc/blob/master/conf.d/ipfw ipfw on OpenRC]

==IPFW Script==
 #!/sbin/openrc-run
 name="ipfw"
 description="Firewall, traffic shaper, packet scheduler, in-kernel NAT"
 firewall_coscripts="natd ${firewall_coscripts}"
 SYSCTL="/sbin/sysctl"
 . /etc/network.subr
 depend() 
 {
 before net
 provide firewall
 keyword -jail -stop -shutdown
 }
 load_kld()
 {
 kldload -nq $1
 }
 start_pre()
 {
 load_kld ipfw
 if yesno dummynet_enable; then
 load_kld "dummynet"
 fi
 if yesno natd_enable; then
 load_kld "ipdivert"
 fi
 if yesno firewall_nat_enable; then
 load_kld "ipfw_nat"
 fi
 }
 start()
 {
 local   _firewall_type
 _firewall_type=$1
 ebegin "Starting $name"
 # set the firewall rules script if none was specified
 [ -z "${firewall_script}" ] && firewall_script='''/etc/ipfw.rules'''
 if [ -r "${firewall_script}" ]; then
 /bin/sh "${firewall_script}" "${_firewall_type}"
 elif [ "`ipfw list 65535`" = "65535 deny ip from any to any" ]; then
 ewarn 'Warning: kernel has firewall functionality, but' \
 ' firewall rules are not enabled.' ewarn '           All ip services are disabled.'
 fi
 # Firewall logging
 #
 if yesno firewall_logging; then
 sysctl net.inet.ip.fw.verbose=1 >/dev/null
 fi
 if yesno firewall_logif; then
 ifconfig ipfw0 create
 fi
 eend 0
 }
 start_post()
 {
 local	_coscript
 # Start firewall coscripts
 #
 for _coscript in ${firewall_coscripts} ; do
 if [ -f "${_coscript}" ]; then
 service ${_coscript} start >/dev/null 2>/dev/null
 fi
 done
 # Enable the firewall
 #
 if ! ${SYSCTL} net.inet.ip.fw.enable=1 1>/dev/null 2>&1; then
 ewarn "failed to enable IPv4 firewall"
 fi
 if afexists inet6; then
 if ! ${SYSCTL} net.inet6.ip6.fw.enable=1 1>/dev/null 2>&1
 then
 ewarn "failed to enable IPv6 firewall"
 fi
 fi
 }
 reverse_list()
 {
 _revlist=
 for _revfile; do
 _revlist="$_revfile $_revlist"
 done
 echo $_revlist
 }
 stop()
 {
 local	_coscript
 # Disable the firewall
 #
 ebegin "Stopping $name"
 ${SYSCTL} net.inet.ip.fw.enable=0
 if afexists inet6; then
 ${SYSCTL} net.inet6.ip6.fw.enable=0
 fi
 # Stop firewall coscripts
 #
 for _coscript in `reverse_list ${firewall_coscripts}` ; do
 if [ -f "${_coscript}" ]; then
 service ${_coscript} stop >/dev/null 2>/dev/null
 fi
 done
 eend 0
 }

==Some ideas about Firewalls==
An interesting article about firewalls you will find on the [https://wiki.gentoo.org/wiki/Security_Handbook/Firewalls Gentoo wiki]. 


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[[Category:Central Station Sysutils]]