ipfw.8 revision 6275
1.Dd November 16, 1994 2.Dt IPFW 8 3.Os 4.Sh NAME 5ipfw - controlling utility for ipfw/ipacct facilities. 6 7.Sh SYNOPSIS 8 9 ipfw [-n] <entry-action> <chain entry pattern> 10 ipfw [-ans] <chain-action> <chain[s] type> 11 12.Sh DESCRIPTION 13 In the first synopsis form, the ipfw utility allows control of firewall 14and accounting chains. 15 In the second synopsis form, the ipfw utility allows setting of global 16firewall/accounting properties and listing of chain contents. 17 18The following options are available: 19 20-a While listing,show counter values-this option is the only way to 21 see accounting records.Works only with -s. 22 23-n Do not resolve anything. When setting entries, do not try to resolve 24 a given address. When listing, display addresses in numeric form. 25 26-s Short listing form.By default listing format is compatible with ipfw 27 input string format,so you can save listings to file and then reuse 28 them. With this option list format is much more short but 29 incompatible with ipfw syntacs. 30 31These are <entry-actions>: 32 33 addf[irewall] - add entry to firewall chain. 34 delf[irewall] - remove entry from firewall chain. 35 adda[ccounting] - add entry to accounting chain. 36 dela[ccounting] - remove entry from accounting chain. 37 clr[accounting] - clear counters for accounting chain entry. 38 39These are <chain-actions>: 40 f[lush] - remove all entries in firewall/accounting chains. 41 l[ist] - show all entries in firewall/accounting chains. 42 z[ero] - clear chain counters(accounting only). 43 p[olicy] - set default policy properties. 44 45This is <chain-entry pattern> structure: 46 For forwarding/blocking chains: 47 vr[eject] <proto/addr pattern> reject packet,send ICMP unreachable and log. 48 r[eject] <proto/addr pattern> reject packet,send ICMP unreachable. 49 vd[eny] <proto/addr pattern> reject packet,log it. 50 d[eny] <proto/addr pattern> reject packet. 51 l[og] <proto/addr pattern> allow packet,log it. 52 va[ccept] <proto/addr pattern> allow packet,log it. 53 a[ccept] <proto/addr pattern> allow packet. 54 For accounting chain: 55 s[ingle] <proto/addr pattern> log packets matching entry. 56 b[idirectional] <proto/addr pattern> log packets matching entry and 57 those going in opposite direction (from entry 58 "dst" to "src"). 59 60The <proto/addr pattern> is: 61 all|icmp from <src addr/mask> to <dst addr/mask> 62 tcp|tcpsyn|udp from <src addr/mask> [ports] to <dst addr/mask> [ports] 63all matches any IP packet. 64icmp,tcp and udp - packets for corresponding protocols. 65tcpsyn - tcp SYN packets (which used when initiating connection). 66 67The <src addr/mask>: 68 <INET IP addr | domain name> [/mask bits | :mask pattern] 69 Mask bits is a decimal number of bits set in the address mask. 70 Mask pattern has form of IP address and AND'ed logically with address given. 71 [ports]: [ port,port....|port:port] 72 Name of service can be used instead of port numeric value. 73 74To l[ist] command may be passed: 75 f[irewall] | a[ccounting] to list specific chain or none to list 76all of chains.Long output format compatible with utility input syntacs. 77 78To f[lush] command may be passed: 79 f[irewall] | a[ccounting] to remove all entries from firewall or 80from accounting chain.Without arguments removes all chain entries. 81 82To z[ero] command no arguments needed,this command clears counters for 83whole accounting chain. 84 85The p[olicy] command can be given a[ccept]|d[eny] to set default policy 86as denial/accepting.Without arguments current default policy displayed. 87 88.Sh EXAMPLES 89 90 This command add entry which denies all tcp packets from 91hacker.evil.org to telnet port of wolf.tambov.su from being 92forwarded by the host: 93 ipfw addf deny tcp from hacker.evil.org to wolf.tambov.su telnet 94 95 This one disallows any connection from entire hackers network 96to my host: 97 ipfw addf deny all from 123.45.67.8/24 to my.host.org 98 99 Here is good usage of list command to see accounting records: 100 ipfw -sa list accounting (or in short form ipfw -sa l a ). 101 102 Much more examples can be found in files: 103 /usr/share/FAQ/ipfw.FAQ (missing for the moment) 104 105.Sh SEE ALSO 106ip(4),ipfirewall(4),ipaccounting(4),reboot(8) 107 108.Sh BUGS 109 WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!!WARNING!! 110 This programm can put your computer in rather unusable state. 111First time try using it from console and do *NOT* do anything 112you don't understand. 113 Remember that "ipfw flush" can solve all the problemms. 114Also take in your mind that "ipfw policy deny" combined with 115some wrong chain entry(possible the only entry which designed 116to deny some external packets), can close your computer from 117outer world for good. 118 119.Sh HISTORY 120 Initially this utility was written for BSDI by: 121 Daniel Boulet <danny@BouletFermat.ab.ca> 122 The FreeBSD version is written completely by: 123 Ugen J.S.Antsilevich <ugen@NetVision.net.il> 124 while synopsis partially compatible with old one. 125