Convert manpage to -mandoc macros.
Submitted by: Gary Palmer <gary@palmer.demon.co.uk> Minor cleanup by me in the English.
This commit is contained in:
Nate Williams
parent
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sbin/ipfw/ipfw.8
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sbin/ipfw/ipfw.8
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.Dd November 16, 1994
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.Dt IPFW 8
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.Os
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.Dt IPFW 8 SMM
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.Os FreeBSD
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.Sh NAME
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ipfw - controlling utility for ipfw/ipacct facilities.
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.Nm ipfw
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.Nd controlling utility for IP firewall / IP accounting facilities.
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.Sh SYNOPSIS
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ipfw [-n] <entry-action> <chain entry pattern>
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ipfw [-ans] <chain-action> <chain[s] type>
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.Nm
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.Oo
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.Fl n
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.Oc
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.Ar entry_action chain_entry_pattern
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.Nm ipfw
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.Oo
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.Fl ans
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.Oc
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.Ar chain_action chain[s]_type
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.\" ipfw [-n] <entry-action> <chain entry pattern>
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.\" ipfw [-ans] <chain-action> <chain[s] type>
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.Sh DESCRIPTION
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In the first synopsis form, the ipfw utility allows control of firewall
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and accounting chains.
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In the second synopsis form, the ipfw utility allows setting of global
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firewall/accounting properties and listing of chain contents.
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In the first synopsis form,
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.Nm
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controls the firewall and accounting chains. In the second
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synopsis form,
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.Nm
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sets the global firewall / accounting properties and
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show the chain list's contents.
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.Pp
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The following options are available:
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.Bl -tag -width flag
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.It Fl a
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While listing, show counter values. This option is the only way to see
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accounting records. Works only with
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.Fl s
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.It Fl n
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Do not resolve anything. When setting entries, do not try to resolve a
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given address. When listing, display addresses in numeric form.
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.It Fl s
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Short listing form. By default, the listing format is compatible with
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.Nm
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input string format, so you can save listings to file and then reuse
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them. With this option list format is much more short but incompatible
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with the
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.Nm
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syntax.
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.El
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.Pp
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These are the valid
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.Ar entry_actions :
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.Bl -hang -offset flag -width 1234567890123456
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.It Nm addf[irewall]
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add entry to firewall chain.
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.It Nm delf[irewall]
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remove entry from firewall chain.
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.It Nm adda[ccounting]
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add entry to accounting chain.
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.It Nm dela[ccounting]
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remove entry from accounting chain.
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.It Nm clr[accounting]
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clear counters for accounting chain entry.
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.El
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.Pp
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If no
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.Ar entry_action
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is specified, it will default to
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.Nm addf[irewall]
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or
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.Nm adda[ccounting] ,
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depending on the
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.Ar chain_entry_pattern
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specified.
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.Pp
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The valid
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.Ar chain_actions
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are:
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.Bl -hang -offset flag -width 123456789
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.It Nm f[lush]
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remove all entries in firewall / accounting chains.
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.It Nm l[ist]
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display all entries in firewall / accounting chains.
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.It Nm z[ero]
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clear chain counters (accounting only).
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.It Nm p[olicy]
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set default policy properties.
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.El
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.Pp
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The
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.Ar chain_entry_pattern
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structure is:
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.Pp
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.Dl [keyword] [protocol] [address pattern]
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.Pp
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For the firewall chain, valid
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.Em keywords
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are:
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.Bl -hang -offset flag -width 12345678
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.It Nm reject
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Reject the packet, and send an
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.Tn ICMP HOST_UNREACHABLE
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packet to the source.
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.It Nm lreject
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The same as
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.Nm reject ,
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but also log the packets details.
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.It Nm deny
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Reject the packet.
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.It Nm ldeny
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The same as
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.Nm deny ,
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but also log the packets details.
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.It Nm log
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Accept the packet, and log it.
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.It Nm accept
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Accept the packet (obviously).
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.It Nm pass
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A synonym for accept.
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.El
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-a While listing,show counter values-this option is the only way to
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see accounting records.Works only with -s.
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-n Do not resolve anything. When setting entries, do not try to resolve
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a given address. When listing, display addresses in numeric form.
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-s Short listing form.By default listing format is compatible with ipfw
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input string format,so you can save listings to file and then reuse
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them. With this option list format is much more short but
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incompatible with ipfw syntacs.
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These are <entry-actions>:
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addf[irewall] - add entry to firewall chain.
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delf[irewall] - remove entry from firewall chain.
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adda[ccounting] - add entry to accounting chain.
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dela[ccounting] - remove entry from accounting chain.
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clr[accounting] - clear counters for accounting chain entry.
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If no <entry-action> specified,default addf[irewall] or add[accounting]
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will be used,depending on <chain-entry pattern> specified.
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These are <chain-actions>:
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f[lush] - remove all entries in firewall/accounting chains.
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l[ist] - show all entries in firewall/accounting chains.
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z[ero] - clear chain counters(accounting only).
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p[olicy] - set default policy properties.
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This is <chain-entry pattern> structure:
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For forwarding/blocking chains:
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lreject <proto/addr pattern> reject packet,send ICMP unreachable and log.
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reject <proto/addr pattern> reject packet,send ICMP unreachable.
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ldeny <proto/addr pattern> reject packet,log it.
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deny <proto/addr pattern> reject packet.
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log <proto/addr pattern> allow packet,log it.
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accept <proto/addr pattern> allow packet.
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pass <proto/addr pattern> allow packet.
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For accounting chain:
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single <proto/addr pattern> log packets matching entry.
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bidirectional <proto/addr pattern> log packets matching entry and
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those going in opposite direction (from entry
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"dst" to "src").
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.Pp
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For the accounting chain, valid
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.Em keywords
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are:
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.Bl -tag -width flag
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.It Nm single
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Log packets matching entry.
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.It Nm bidirectional
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Log packets matching entry and also those going in the
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opposite direction (from
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.Dq dst
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to
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.Dq src ) .
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.El
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.Pp
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Each keyword will be recognized by the shortest unambigious prefix.
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The <proto/addr pattern> is:
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all|icmp from <src addr/mask> to <dst addr/mask> [via <via>]
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tcp[syn]|udp from <src addr/mask>[ports] to <dst addr/mask>[ports][via <via>]
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all matches any IP packet.
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icmp,tcp and udp - packets for corresponding protocols.
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syn - tcp SYN packets (which used when initiating connection).
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The order of from/to/via keywords is unimportant.You can skip any
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of them,which will be then substituted by default entry matching
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any from/to/via packet kind.
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The <src addr/mask>:
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<INET IP addr | domain name> [/mask bits | :mask pattern]
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Mask bits is a decimal number of bits set in the address mask.
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Mask pattern has form of IP address and AND'ed logically with address given.
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Keyword "any" can be used to specify 'any IP'.
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[ports]: [ port,port....|port:port]
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Name of service can be used instead of port numeric value.
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The via <via> is optional and may specify IP address/domain name of local
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IP interface, or interface name (e.g. ed0) to match only packets coming
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through this interface.The IP or name given is NOT checked, and wrong
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value of IP causes entry to not match anything.
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Keyword 'via' can be substituted by 'on',for readability reasons.
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To l[ist] command may be passed:
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f[irewall] | a[ccounting] to list specific chain or none to list
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all of chains.Long output format compatible with utility input syntacs.
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To f[lush] command may be passed:
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f[irewall] | a[ccounting] to remove all entries from firewall or
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from accounting chain.Without arguments removes all chain entries.
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To z[ero] command no arguments needed,this command clears counters for
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whole accounting chain.
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The p[olicy] command can be given a[ccept]|d[eny] to set default policy
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as denial/accepting.Without arguments current default policy displayed.
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.Pp
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Recognised
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.Em protocols
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are:
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.Bl -hang -offset flag -width 123456
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.It Nm all
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Matches any IP packet.
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.It Nm icmp
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Matches ICMP packets.
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.It Nm tcp
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Matches TCP packets.
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.It Nm udp
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Matches UDP packets.
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.It Nm syn
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Matches the TCP SYN packet used in initiating a TCP connection. It
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does not match the packet returned from a destination machine which
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has the SYN and ACK bits set.
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.El
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.Pp
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The
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.Em address pattern
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is:
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.Pp
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.Dl from <address/mask>[ports] to <address/mask][ports] [via <interface>]
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.Pp
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You can only specify
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.Em ports
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with
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.Em protocols
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which actually have ports (TCP, UDP and SYN).
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.Pp
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The order of
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.Sq from/to/via
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keywords is unimportant. You can skip any of them, which will be
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then substituted by default entry matching any
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.Sq from/to/via
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packet kind.
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.Pp
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The
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.Em <address/mask>
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is defined as:
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.Pp
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.Dl <address|name>[/mask_bits|:mask_pattern]
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.Pp
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.Em mask bits
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is the decimal number of bits set in the address mask.
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.Em mask pattern
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has the form of an IP address to be AND'ed logically with the address
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given. The keyword
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.Em any
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can be used to specify
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.Dq any IP .
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The IP address or name given is
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.Em NOT
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checked, and the wrong value
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causes the entry to not match anything.
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.Pp
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The
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.Em ports
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to be blocked are specified as:
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.Dl Ns port Ns Op ,port Ns Op ,...
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or:
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.Dl port:port
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.Pp
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to specify a range of ports. The name of a service (from
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.Pa /etc/services )
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can be used instead of
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a numeric port value.
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.Pp
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The
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.Em via <interface>
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entry is optional and may specify IP address/domain name of local IP
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interface, or interface name (e.g.
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.Em ed0 )
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to match only packets coming
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through this interface. The keyword
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.Em via
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can be substituted by
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.Em on ,
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for readability reasons.
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.Pp
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The
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.Em l[ist]
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command may be passed:
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.Pp
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.Dl f[irewall] | a[ccounting]
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.Pp
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to list specific chain or none to list all of chains. The long output
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format (default) is compatible with the syntax used by the
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.Nm
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utility.
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.Pp
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The
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.Em f[lush]
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command may be passed:
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.Pp
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.Dl f[irewall] | a[ccounting]
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.Pp
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to remove all entries from firewall or from accounting chain. Without
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an argument it will remove all entries from both chains.
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.Pp
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The
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.Em z[ero]
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command needs no arguments. This command clears all counters for the
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entire accounting chain.
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.Pp
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The
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.Em p[olicy]
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command can be given
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.Pp
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.Dl a[ccept] | d[eny]
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.Pp
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to set default policy as denial/acceptance. Without an angument, the
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current policy status is displayed.
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.Sh EXAMPLES
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This command add entry which denies all tcp packets from
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hacker.evil.org to telnet port of wolf.tambov.su from being
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forwarded by the host:
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ipfw addf deny tcp from hacker.evil.org to wolf.tambov.su telnet
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This one disallows any connection from entire hackers network
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to my host:
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ipfw addf deny all from 123.45.67.8/24 to my.host.org
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Here is good usage of list command to see accounting records:
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ipfw -sa list accounting (or in short form ipfw -sa l a ).
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Much more examples can be found in files:
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/usr/share/FAQ/ipfw.FAQ (missing for the moment)
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This command adds an entry which denies all tcp packets from
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.Em hacker.evil.org
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to the telnet port of
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.Em wolf.tambov.su
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from being forwarded by the host:
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.Pp
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.Dl ipfw addf deny tcp from hacker.evil.org to wolf.tambov.su telnet
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.Pp
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This one disallows any connection from the entire hackers network to
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my host:
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.Pp
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.Dl ipfw addf deny all from 123.45.67.0/24 to my.host.org
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.Pp
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Here is good usage of list command to see accounting records:
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.Pp
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.Dl ipfw -sa list accounting
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.Pp
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or in short form
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.Pp
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.Dl ipfw -sa l a
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.Pp
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Many more examples can be found in the file:
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.Dl Pa /usr/share/FAQ/ipfw.FAQ
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(missing for the moment)
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.Sh SEE ALSO
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ip(4),ipfirewall(4),ipaccounting(4),reboot(8)
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.Xr gethostbyname 3 ,
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.Xr getservbyport 3 ,
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.Xr ip 4 ,
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.Xr ipfirewall 4 ,
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.Xr ipaccounting 4 ,
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.Xr reboot 8 ,
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.Xr syslogd 8
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.Sh BUGS
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WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!
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This programm can put your computer in rather unusable state.
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First time try using it from console and do *NOT* do anything
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you don't understand.
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Remember that "ipfw flush" can solve all the problemms.
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Also take in your mind that "ipfw policy deny" combined with
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some wrong chain entry(possible the only entry which designed
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to deny some external packets), can close your computer from
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outer world for good.
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Currently there is no method for filtering out specific types of ICMP
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packets. Either you don't filter ICMP at all, or all ICMP packets are
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filtered.
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.Pp
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The system has a rule weighting system for the firewall chain. This
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means that rules are not used in the order that they are specified. To
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see what rule ordering is used, use the
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.Em list
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command.
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.Pp
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.Em WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!
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.Pp
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This program can put your computer in rather unusable state. When
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using it for the first time, work on the console of the computer, and
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do
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.Em NOT
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do anything you don't understand.
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.Pp
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Remember that
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.Dq ipfw flush
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can solve all the problems. Bear in mind that
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.Dq ipfw policy deny
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combined with some wrong chain entry (possible the only entry, which
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is designed to deny some external packets), can close your computer
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from the outer world for good (or at least until you can get to the
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console).
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.Sh HISTORY
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Initially this utility was written for BSDI by:
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Daniel Boulet <danny@BouletFermat.ab.ca>
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The FreeBSD version is written completely by:
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Ugen J.S.Antsilevich <ugen@NetVision.net.il>
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while synopsis partially compatible with old one.
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Initially this utility was written for BSDI by:
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.Pp
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.Dl Daniel Boulet <danny@BouletFermat.ab.ca>
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.Pp
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The FreeBSD version is written completely by:
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.Pp
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.Dl Ugen J.S.Antsilevich <ugen@FreeBSD.ORG>
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.Pp
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while the synopsis is partially compatible with the old one.
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