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129 lines
4.6 KiB
Groff
129 lines
4.6 KiB
Groff
.Dd November 16, 1994
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.Dt IPFW 8
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.Os
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.Sh NAME
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ipfw - controlling utility for ipfw/ipacct facilities.
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.Sh SYNOPSIS
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ipfw [-vn] <entry-action> <chain entry pattern>
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ipfw [-vn] <check-action> <packet pattern>
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ipfw [-vn] <chain-action> <chain[s] type>
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.Sh DESCRIPTION
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In the first synopsis form, the ipfw utility allows adding/removing of
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entries of blocking/forwarding/accounting chains.
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In the second synopsis form, the ipfw utility checks whenever a given
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IP packet type is accepted or denied by a blocking/forwarding firewall.
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In the third synopsis form, the ipfw utility allows global actions
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on chain-zeroing of counters, and flushing or listing of chain entries
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and their counter values.
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The following options are available:
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-v be verbose. The meaning of this option varies depending on ipfw
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usage.
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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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These are <entry-actions>:
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addb[locking] - add entry to blocking firewall.
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delb[locking] - remove entry from blocking firewall.
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addf[orwarding] - add entry to forwarding firewall.
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delf[orwarding] - remove entry from forwarding firewall.
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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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These are <check-actions>:
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checkb[locking] - check packet against blocking firewall.
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checkf[orwarding] - check packet against forwarding firewall.
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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 blocking/forwarding/accounting chains.
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z[ero] - clear chain counters(for now accounting only).
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p[olicy] - define default firewall policy.
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The <chain-entry pattern> build like this:
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For forwarding/blocking chains:
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d[eny] <proto/addr pattern>
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a[ccept] <proto/addr pattern>
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For accounting chain:
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s[ingle] <proto/addr pattern>
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b[idirectional] <proto/addr pattern>
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The <proto/addr pattern> is:
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all|icmp from <src addr/mask> to <dst addr/mask>
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tcp|udp from <src addr/mask> [ports] to <dst addr/mask> [ports]
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<src addr/mask>:
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<INET IP addr | domain name> [/mask bits | :mask pattern]
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[ports]:
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[ port,port....|port:port] where name of service can be
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used instead of port numeric value.
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When entry added to chain and -v option used,entry added with
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PRN flag set.
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The <packet pattern> build exactly like <chain-entry pattern>.
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To l[ist] command may be passed:
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f[orwarding]|b[locking]|a[ccounting] to list specific chain or none
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to list all of them.Option -v causes output format to change so that
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packet/bytes counters printed.Standart output format fully suitable
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to be used as <chain-entry pattern>.
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To f[lush] command may be passed:
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f[irewall]|a[ccounting] to remove all entries from forwarding/blocking
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chains or from accounting chain.No arguments removes all chain entries.
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To z[ero] command no arguments needed,and all counters of accounting
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chain zeroed.
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To p[olicy] command accepts a[ccept]|d[eny] to define default policy
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as denial/accepting.Withno arguments current default policy 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 addb deny all from 123.45.67.8/24 to my.host.org
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Here is useful usage of lt] command to see accounting records:
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ipfw -v list accounting (or in short form ipfw -v l a ).
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Much more examples can be found in files:
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/usr/share/misc/ipfw.samp.filters
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/usr/share/misc/ipfw.samp.scripts
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.Sh SEE ALSO
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ipfirewall(4),ipaccounting(4),reboot(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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Besides of misuse the only known bug is that entry added
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with -v option set should be deleted with same option,
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but there is no way to see this in list command.
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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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