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- mdoc(7) style cleanup
- new version of security note from alex.
This commit is contained in:
Ruslan Ermilov
parent
0ae3b944b5
commit
5a424c8cc0
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=62157
580
sbin/natd/natd.8
580
sbin/natd/natd.8
@ -1,152 +1,176 @@
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.\" manual page [] for natd 1.4
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.\" $FreeBSD$
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.Dd 15 April 1997
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.Os FreeBSD
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.Dd June 27, 2000
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.Dt NATD 8
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.Os FreeBSD
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.Sh NAME
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.Nm natd
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.Nd
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Network Address Translation Daemon
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.Nd Network Address Translation Daemon
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.Sh SYNOPSIS
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.Nm
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.Op Fl ldsmvu
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.Nm natd
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.Op Fl unregistered_only | u
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||||
.Op Fl log | l
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.Op Fl proxy_only
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.Op Fl reverse
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.Op Fl deny_incoming | d
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.Op Fl use_sockets | s
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.Op Fl same_ports | m
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.Op Fl verbose | v
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.Op Fl dynamic
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.Op Fl i Ar inport
|
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.Op Fl o Ar outport
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.Op Fl p Ar port
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.Op Fl a Ar address
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.Op Fl t Ar address
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.Op Fl n Ar interface
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.Op Fl f Ar configfile
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.Nm
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.Op Fl log
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.Op Fl deny_incoming
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.Op Fl log_denied
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.Op Fl use_sockets
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.Op Fl same_ports
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.Op Fl verbose
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.Op Fl log_facility Ar facility_name
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.Op Fl unregistered_only
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.Op Fl dynamic
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.Op Fl inport Ar inport
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.Op Fl outport Ar outport
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.Op Fl port Ar port
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.Op Fl alias_address Ar address
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.Op Fl target_address Ar address
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.Op Fl interface Ar interface
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.Op Fl config Ar configfile
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.Op Fl in_port | i Ar port
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.Op Fl out_port | o Ar port
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.Op Fl port | p Ar port
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.Op Fl alias_address | a Ar address
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.Op Fl target_address | t Ar address
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.Op Fl interface | n Ar interface
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.Op Fl proxy_rule Ar proxyspec
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.Op Fl redirect_port Ar linkspec
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.Op Fl redirect_proto Ar linkspec
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.Op Fl redirect_address Ar linkspec
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.Op Fl reverse
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.Op Fl proxy_only
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.Op Fl proxy_rule Ar proxyspec
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.Op Fl config | f Ar configfile
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.Op Fl log_denied
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.Op Fl log_facility Ar facility_name
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.Sh DESCRIPTION
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This program provides a Network Address Translation facility for use
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with
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.Xr divert 4
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sockets under FreeBSD. It is intended for use with NICs - if you want
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to do NAT on a PPP link, use the -nat switch to
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sockets under
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.Fx .
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It is intended for use with NICs - if you want to do NAT on a PPP link,
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use the
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.Fl nat
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switch to
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.Xr ppp 8 .
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.Pp
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.Nm Natd
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||||
normally runs in the background as a daemon. It is passed raw IP packets
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as they travel into and out of the machine, and will possibly change these
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before re-injecting them back into the IP packet stream.
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The
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.Nm
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normally runs in the background as a daemon.
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It is passed raw IP packets as they travel into and out of the machine,
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and will possibly change these before re-injecting them back into the
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IP packet stream.
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.Pp
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.Nm Natd
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changes all packets destined for another host so that their source
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IP number is that of the current machine. For each packet changed
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in this manner, an internal table entry is created to record this
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fact. The source port number is also changed to indicate the
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table entry applying to the packet. Packets that are received with
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a target IP of the current host are checked against this internal
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table. If an entry is found, it is used to determine the correct
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target IP number and port to place in the packet.
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|
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It changes all packets destined for another host so that their source
|
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IP number is that of the current machine.
|
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For each packet changed in this manner, an internal table entry is
|
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created to record this fact.
|
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The source port number is also changed to indicate the table entry
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applying to the packet.
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Packets that are received with a target IP of the current host are
|
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checked against this internal table.
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If an entry is found, it is used to determine the correct target IP
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number and port to place in the packet.
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.Pp
|
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The following command line options are available.
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.Bl -tag -width Fl
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.It Fl log | l
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Log various aliasing statistics and information to the file
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.Pa /var/log/alias.log .
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This file is truncated each time natd is started.
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This file is truncated each time
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.Nm
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is started.
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.It Fl deny_incoming | d
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Reject packets destined for the current IP number that have no entry
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in the internal translation table.
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Do not pass packets destined for the current IP number that have no
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entry in the internal translation table.
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.It Fl log_denied
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Log denied incoming packets via syslog (see also log_facility)
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Log denied incoming packets via
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.Xr syslog 3
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.Po
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see also
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.Fl log_facility
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.Pc .
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.It Fl log_facility Ar facility_name
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Use specified log facility when logging information via syslog.
|
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Facility names are as in
|
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.Xr syslog.conf 5
|
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|
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Use specified log facility when logging information via
|
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.Xr syslog 3 .
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Argument
|
||||
.Ar facility_name
|
||||
is one of the keywords specified in
|
||||
.Xr syslog.conf 5 .
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.It Fl use_sockets | s
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Allocate a
|
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.Xr socket 2
|
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in order to establish an FTP data or IRC DCC send connection. This
|
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option uses more system resources, but guarantees successful connections
|
||||
when port numbers conflict.
|
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|
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in order to establish an FTP data or IRC DCC send connection.
|
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This option uses more system resources, but guarantees successful
|
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connections when port numbers conflict.
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.It Fl same_ports | m
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Try to keep the same port number when altering outgoing packets.
|
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With this option, protocols such as RPC will have a better chance
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of working. If it is not possible to maintain the port number, it
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will be silently changed as per normal.
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of working.
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||||
If it is not possible to maintain the port number, it will be silently
|
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changed as per normal.
|
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.It Fl verbose | v
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Don't call
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.Xr fork 2
|
||||
or
|
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Do not call
|
||||
.Xr daemon 3
|
||||
on startup. Instead, stay attached to the controling terminal and
|
||||
display all packet alterations to the standard output. This option
|
||||
should only be used for debugging purposes.
|
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on startup.
|
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Instead, stay attached to the controling terminal and display all packet
|
||||
alterations to the standard output.
|
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This option should only be used for debugging purposes.
|
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.It Fl unregistered_only | u
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Only alter outgoing packets with an unregistered source address.
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According to rfc 1918, unregistered source addresses are 10.0.0.0/8,
|
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Only alter outgoing packets with an
|
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.Em unregistered
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source address.
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According to RFC 1918, unregistered source addresses are 10.0.0.0/8,
|
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172.16.0.0/12 and 192.168.0.0/16.
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.It Fl redirect_port Ar proto targetIP:targetPORT[-targetPORT] [aliasIP:]aliasPORT[-aliasPORT] [remoteIP[:remotePORT[-remotePORT]]]
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.It Fl redirect_port Ar proto Xo
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.Ar targetIP Ns : Ns Xo
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.Ar targetPORT Ns Op - Ns Ar targetPORT Xc
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.Op Ar aliasIP Ns : Ns Xo
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.Ar aliasPORT Ns Op - Ns Ar aliasPORT Xc
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.Oo Ar remoteIP Ns Oo : Ns
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.Ar remotePORT Ns Op - Ns Ar remotePORT
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.Oc Oc
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.Xc
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Redirect incoming connections arriving to given port(s) to another host
|
||||
and port(s).
|
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Proto is either tcp or udp, targetIP is the desired target IP
|
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number, targetPORT is the desired target PORT number or range, aliasPORT
|
||||
is the requested PORT number or range, and aliasIP is the aliasing address.
|
||||
RemoteIP and remotePORT can be used to specify the connection
|
||||
more accurately if necessary.
|
||||
The targetPORT range and aliasPORT range need not be the same numerically,
|
||||
but must have the same size.
|
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If remotePORT is not specified, it is assumed to be all ports.
|
||||
If remotePORT is specified, it must match the size of targetPORT, or be 0
|
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(all ports).
|
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Argument
|
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.Ar proto
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is either
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.Ar tcp
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or
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.Ar udp ,
|
||||
.Ar targetIP
|
||||
is the desired target IP number,
|
||||
.Ar targetPORT
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||||
is the desired target port number or range,
|
||||
.Ar aliasPORT
|
||||
is the requested port number or range, and
|
||||
.Ar aliasIP
|
||||
is the aliasing address.
|
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Arguments
|
||||
.Ar remoteIP
|
||||
and
|
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.Ar remotePORT
|
||||
can be used to specify the connection more accurately if necessary.
|
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The
|
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.Ar targetPORT
|
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range and
|
||||
.Ar aliasPORT
|
||||
range need not be the same numerically, but must have the same size.
|
||||
If
|
||||
.Ar remotePORT
|
||||
is not specified, it is assumed to be all ports.
|
||||
If
|
||||
.Ar remotePORT
|
||||
is specified, it must match the size of
|
||||
.Ar targetPORT ,
|
||||
or be 0 (all ports).
|
||||
For example, the argument
|
||||
|
||||
.Pp
|
||||
.Dl Ar tcp inside1:telnet 6666
|
||||
|
||||
means that incoming tcp packets destined for port 6666 on this machine will
|
||||
be sent to the telnet port on the inside1 machine.
|
||||
|
||||
.Pp
|
||||
means that incoming TCP packets destined for port 6666 on this machine
|
||||
will be sent to the telnet port on the inside1 machine.
|
||||
.Pp
|
||||
.Dl Ar tcp inside2:2300-2399 3300-3399
|
||||
|
||||
.Pp
|
||||
will redirect incoming connections on ports 3300-3399 to host
|
||||
inside2, ports 2300-2399.
|
||||
The mapping is 1:1 meaning port 3300 maps to 2300, 3301 maps to 2301, etc.
|
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.It Fl redirect_proto Ar proto localIP Xo
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.Op Ar publicIP Op Ar remoteIP
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.Xc
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.It Fl redirect_proto Ar proto localIP Oo
|
||||
.Ar publicIP Op Ar remoteIP
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.Oc
|
||||
Redirect incoming IP packets of protocol
|
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.Ar proto
|
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.Pq see Xr protocols 5
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.Po see Xr protocols 5
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.Pc
|
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destined for
|
||||
.Ar publicIP
|
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address to a
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@ -164,26 +188,30 @@ will match the rule.
|
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.It Fl redirect_address Ar localIP publicIP
|
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Redirect traffic for public IP address to a machine on the local
|
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network.
|
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This function is known as "static NAT". Normally static NAT
|
||||
is useful if your ISP has allocated a small block of IP addresses to you,
|
||||
but it can even be used in the case of single address:
|
||||
|
||||
redirect_address 10.0.0.8 0.0.0.0
|
||||
|
||||
This function is known as
|
||||
.Em static NAT .
|
||||
Normally static NAT is useful if your ISP has allocated a small block
|
||||
of IP addresses to you, but it can even be used in the case of single
|
||||
address:
|
||||
.Pp
|
||||
.Dl Ar redirect_address 10.0.0.8 0.0.0.0
|
||||
.Pp
|
||||
The above command would redirect all incoming traffic
|
||||
to machine 10.0.0.8.
|
||||
|
||||
.Pp
|
||||
If several address aliases specify the same public address
|
||||
as follows
|
||||
|
||||
redirect_address 192.168.0.2 public_addr
|
||||
redirect_address 192.168.0.3 public_addr
|
||||
redirect_address 192.168.0.4 public_addr
|
||||
|
||||
.Bd -literal -offset indent
|
||||
.Ar redirect_address 192.168.0.2 public_addr
|
||||
.Ar redirect_address 192.168.0.3 public_addr
|
||||
.Ar redirect_address 192.168.0.4 public_addr
|
||||
.Ed
|
||||
.Pp
|
||||
the incoming traffic will be directed to the last
|
||||
translated local address (192.168.0.4), but outgoing
|
||||
traffic to the first two addresses will still be aliased
|
||||
to specified public address.
|
||||
traffic from the first two addresses will still be aliased
|
||||
to appear from the specified
|
||||
.Ar public_addr .
|
||||
.It Fl redirect_port Ar proto Xo
|
||||
.Ar targetIP Ns : Ns Xo
|
||||
.Ar targetPORT Ns Oo , Ns
|
||||
@ -232,66 +260,63 @@ option is used,
|
||||
.Nm
|
||||
will monitor the routing socket for alterations to the
|
||||
.Ar interface
|
||||
passed. If the interfaces IP number is changed,
|
||||
passed.
|
||||
If the interface's IP number is changed,
|
||||
.Nm
|
||||
will dynamically alter its concept of the alias address.
|
||||
|
||||
.It Fl i | inport Ar inport
|
||||
Read from and write to
|
||||
.Ar inport ,
|
||||
treating all packets as packets coming into the machine.
|
||||
|
||||
.It Fl o | outport Ar outport
|
||||
Read from and write to
|
||||
.Ar outport ,
|
||||
treating all packets as packets going out of the machine.
|
||||
|
||||
.It Fl p | port Ar port
|
||||
.It Fl in_port | i Ar port
|
||||
Read from and write to
|
||||
.Ar port ,
|
||||
distinguishing packets as incoming our outgoing using the rules specified in
|
||||
treating all packets as packets coming into the machine.
|
||||
.It Fl out_port | o Ar port
|
||||
Read from and write to
|
||||
.Ar port ,
|
||||
treating all packets as packets going out of the machine.
|
||||
.It Fl port | p Ar port
|
||||
Read from and write to
|
||||
.Ar port ,
|
||||
distinguishing packets as incoming our outgoing using the rules
|
||||
specified in
|
||||
.Xr divert 4 .
|
||||
If
|
||||
.Ar port
|
||||
is not numeric, it is searched for in the
|
||||
.Pa /etc/services
|
||||
database using the
|
||||
.Xr getservbyname 3
|
||||
function. If this flag is not specified, the divert port named natd will
|
||||
be used as a default. An example entry in the
|
||||
.Pa /etc/services
|
||||
database would be:
|
||||
|
||||
natd 8668/divert # Network Address Translation socket
|
||||
|
||||
Refer to
|
||||
.Xr services 5
|
||||
for further details.
|
||||
|
||||
.It Fl a | alias_address Ar address
|
||||
database.
|
||||
If this option is not specified, the divert port named
|
||||
.Em natd
|
||||
will be used as a default.
|
||||
.It Fl alias_address | a Ar address
|
||||
Use
|
||||
.Ar address
|
||||
as the alias address. If this option is not specified, the
|
||||
.Fl n
|
||||
or
|
||||
as the aliasing address.
|
||||
If this option is not specified, the
|
||||
.Fl interface
|
||||
option must be used. The specified address should be the address assigned
|
||||
to the public network interface.
|
||||
option must be used.
|
||||
The specified address is usually the address assigned to the
|
||||
public network interface.
|
||||
.Pp
|
||||
All data passing out through this addresses interface will be rewritten
|
||||
with a source address equal to
|
||||
All data passing
|
||||
.Em out
|
||||
will be rewritten with a source address equal to
|
||||
.Ar address .
|
||||
All data arriving at the interface from outside will be checked to
|
||||
see if it matches any already-aliased outgoing connection. If it does,
|
||||
the packet is altered accordingly. If not, all
|
||||
.Fl redirect_port
|
||||
All data coming
|
||||
.Em in
|
||||
will be checked to see if it matches any already-aliased outgoing
|
||||
connection.
|
||||
If it does, the packet is altered accordingly.
|
||||
If not, all
|
||||
.Fl redirect_port ,
|
||||
.Fl redirect_proto
|
||||
and
|
||||
.Fl redirect_address
|
||||
assignments are checked and actioned. If no other action can be made,
|
||||
and if
|
||||
assignments are checked and actioned.
|
||||
If no other action can be made and if
|
||||
.Fl deny_incoming
|
||||
is not specified, the packet is delivered to the local machine and port
|
||||
as specified in the packet.
|
||||
is not specified, the packet is delivered unaltered to the local
|
||||
machine and port as specified in the packet, but see the
|
||||
.Fl target_address
|
||||
option below.
|
||||
.It Fl t | target_address Ar address
|
||||
Set the target address.
|
||||
When an incoming packet not associated with any pre-existing link
|
||||
@ -299,171 +324,170 @@ arrives at the host machine, it will be sent to the specified
|
||||
.Ar address .
|
||||
.Pp
|
||||
The target address may be set to
|
||||
.Dq 255.255.255.255 ,
|
||||
.Ar 255.255.255.255 ,
|
||||
in which case all new incoming packets go to the alias address set by
|
||||
.Fl alias_address
|
||||
or
|
||||
.Fl interface .
|
||||
.Pp
|
||||
If this option is not used, or called with the argument
|
||||
.Dq 0.0.0.0 ,
|
||||
.Ar 0.0.0.0 ,
|
||||
then all new incoming packets go to the address specified in
|
||||
the packet.
|
||||
This allows external machines to talk directly to internal machines if
|
||||
they can route packets to the machine in question.
|
||||
.It Fl n | interface Ar interface
|
||||
.It Fl interface | n Ar interface
|
||||
Use
|
||||
.Ar interface
|
||||
to determine the alias address. If there is a possibility that the
|
||||
IP number associated with
|
||||
to determine the aliasing address.
|
||||
If there is a possibility that the IP number associated with
|
||||
.Ar interface
|
||||
may change, the
|
||||
.Fl dynamic
|
||||
flag should also be used. If this option is not specified, the
|
||||
.Fl a
|
||||
or
|
||||
option should also be used.
|
||||
If this option is not specified, the
|
||||
.Fl alias_address
|
||||
flag must be used.
|
||||
option must be used.
|
||||
.Pp
|
||||
The specified
|
||||
.Ar interface
|
||||
must be the public network interface.
|
||||
.It Fl f | config Ar configfile
|
||||
is usually the public network interface.
|
||||
.It Fl config | f Ar file
|
||||
Read configuration from
|
||||
.Ar configfile .
|
||||
.Ar Configfile
|
||||
contains a list of options, one per line in the same form as the
|
||||
long form of the above command line flags. For example, the line
|
||||
|
||||
alias_address 158.152.17.1
|
||||
|
||||
would specify an alias address of 158.152.17.1. Options that don't
|
||||
take an argument are specified with an option of
|
||||
.Ar file .
|
||||
A
|
||||
.Ar file
|
||||
should contain a list of options, one per line, in the same form
|
||||
as the long form of the above command line options.
|
||||
For example, the line
|
||||
.Pp
|
||||
.Dl alias_address 158.152.17.1
|
||||
.Pp
|
||||
would specify an alias address of 158.152.17.1.
|
||||
Options that do not take an argument are specified with an option of
|
||||
.Ar yes
|
||||
or
|
||||
.Ar no
|
||||
in the configuration file. For example, the line
|
||||
|
||||
log yes
|
||||
|
||||
is synonomous with
|
||||
in the configuration file.
|
||||
For example, the line
|
||||
.Pp
|
||||
.Dl log yes
|
||||
.Pp
|
||||
is synonymous with
|
||||
.Fl log .
|
||||
.Pp
|
||||
Trailing spaces and empty lines are ignored.
|
||||
A
|
||||
.Ql \&#
|
||||
sign will mark the rest of the line as a comment.
|
||||
|
||||
.It Fl reverse
|
||||
Reverse operation of natd.
|
||||
This can be useful in some
|
||||
transparent proxying situations when outgoing traffic
|
||||
is redirected to the local machine and natd is running on the
|
||||
incoming interface (it usually runs on the outgoing interface).
|
||||
|
||||
This option makes
|
||||
.Nm
|
||||
reverse the way it handles incoming and outgoing packets,
|
||||
allowing it to operate on the internal interface rather than
|
||||
the external one.
|
||||
.Pp
|
||||
This can be useful in some transparent proxying situations
|
||||
when outgoing traffic is redirected to the local machine
|
||||
and
|
||||
.Nm
|
||||
is running on the internal interface (it usually runs on the
|
||||
external interface).
|
||||
.It Fl proxy_only
|
||||
Force natd to perform transparent proxying
|
||||
only.
|
||||
Force
|
||||
.Nm
|
||||
to perform transparent proxying only.
|
||||
Normal address translation is not performed.
|
||||
|
||||
.It Fl proxy_rule Ar [type encode_ip_hdr|encode_tcp_stream] port xxxx server a.b.c.d:yyyy
|
||||
.It Fl proxy_rule Xo
|
||||
.Op Ar type encode_ip_hdr | encode_tcp_stream
|
||||
.Ar port xxxx
|
||||
.Ar server a.b.c.d:yyyy
|
||||
.Xc
|
||||
Enable transparent proxying.
|
||||
Packets with the given port going through this
|
||||
Outgoing TCP packets with the given port going through this
|
||||
host to any other host are redirected to the given server and port.
|
||||
Optionally, the original target address can be encoded into the packet.
|
||||
Use
|
||||
.Dq encode_ip_hdr
|
||||
Use
|
||||
.Ar encode_ip_hdr
|
||||
to put this information into the IP option field or
|
||||
.Dq encode_tcp_stream
|
||||
.Ar encode_tcp_stream
|
||||
to inject the data into the beginning of the TCP stream.
|
||||
.El
|
||||
|
||||
.Sh RUNNING NATD
|
||||
The following steps are necessary before attempting to run
|
||||
.Nm natd :
|
||||
|
||||
.Bl -enum
|
||||
.It
|
||||
Get FreeBSD version 2.2 or higher. Versions before this do not support
|
||||
.Xr divert 4
|
||||
sockets.
|
||||
|
||||
.It
|
||||
Build a custom kernel with the following options:
|
||||
|
||||
options IPFIREWALL
|
||||
options IPDIVERT
|
||||
|
||||
.Bd -literal -offset indent
|
||||
options IPFIREWALL
|
||||
options IPDIVERT
|
||||
.Ed
|
||||
.Pp
|
||||
Refer to the handbook for detailed instructions on building a custom
|
||||
kernel.
|
||||
|
||||
.It
|
||||
Ensure that your machine is acting as a gateway. This can be done by
|
||||
specifying the line
|
||||
|
||||
gateway_enable=YES
|
||||
|
||||
in
|
||||
.Pa /etc/rc.conf ,
|
||||
or using the command
|
||||
|
||||
sysctl -w net.inet.ip.forwarding=1
|
||||
|
||||
Ensure that your machine is acting as a gateway.
|
||||
This can be done by specifying the line
|
||||
.Pp
|
||||
.Dl gateway_enable=YES
|
||||
.Pp
|
||||
in the
|
||||
.Pa /etc/rc.conf
|
||||
file or using the command
|
||||
.Pp
|
||||
.Dl sysctl -w net.inet.ip.forwarding=1
|
||||
.Pp
|
||||
.It
|
||||
If you wish to use the
|
||||
.Fl n
|
||||
or
|
||||
If you use the
|
||||
.Fl interface
|
||||
flags, make sure that your interface is already configured. If, for
|
||||
example, you wish to specify tun0 as your
|
||||
option, make sure that your interface is already configured.
|
||||
If, for example, you wish to specify tun0 as your
|
||||
.Ar interface ,
|
||||
and you're using
|
||||
and you are using
|
||||
.Xr ppp 8
|
||||
on that interface, you must make sure that you start
|
||||
.Nm ppp
|
||||
prior to starting
|
||||
.Nm natd .
|
||||
|
||||
.It
|
||||
Create an entry in
|
||||
.Pa /etc/services :
|
||||
|
||||
natd 8668/divert # Network Address Translation socket
|
||||
|
||||
This gives a default for the
|
||||
.Fl p
|
||||
or
|
||||
.Fl port
|
||||
flag.
|
||||
|
||||
.El
|
||||
.Pp
|
||||
Running
|
||||
.Nm
|
||||
is fairly straight forward. The line
|
||||
|
||||
natd -interface ed0
|
||||
|
||||
should suffice in most cases (substituting the correct interface name). Once
|
||||
is fairly straight forward.
|
||||
The line
|
||||
.Pp
|
||||
.Dl natd -interface ed0
|
||||
.Pp
|
||||
should suffice in most cases (substituting the correct interface name).
|
||||
Once
|
||||
.Nm
|
||||
is running, you must ensure that traffic is diverted to natd:
|
||||
|
||||
is running, you must ensure that traffic is diverted to
|
||||
.Nm natd :
|
||||
.Bl -enum
|
||||
.It
|
||||
You will need to adjust the
|
||||
.Pa /etc/rc.firewall
|
||||
script to taste. If you're not interested in having a firewall, the
|
||||
script to taste.
|
||||
If you are not interested in having a firewall, the
|
||||
following lines will do:
|
||||
|
||||
/sbin/ipfw -f flush
|
||||
/sbin/ipfw add divert natd all from any to any via ed0
|
||||
/sbin/ipfw add pass all from any to any
|
||||
|
||||
The second line depends on your interface (change ed0 as appropriate)
|
||||
and assumes that you've updated
|
||||
.Pa /etc/services
|
||||
with the natd entry as above. If you specify real firewall rules, it's
|
||||
best to specify line 2 at the start of the script so that
|
||||
.Bd -literal -offset indent
|
||||
/sbin/ipfw -f flush
|
||||
/sbin/ipfw add divert natd all from any to any via ed0
|
||||
/sbin/ipfw add pass all from any to any
|
||||
.Ed
|
||||
.Pp
|
||||
The second line depends on your interface (change ed0 as appropriate).
|
||||
.Pp
|
||||
You should be aware of the fact that, with these firewall settings,
|
||||
everyone on your local network can fake his source-address using your
|
||||
host as gateway.
|
||||
If there are other hosts on your local network, you are strongly
|
||||
encouraged to create firewall rules that only allow traffic to and
|
||||
from trusted hosts.
|
||||
.Pp
|
||||
If you specify real firewall rules, it is best to specify line 2 at
|
||||
the start of the script so that
|
||||
.Nm
|
||||
sees all packets before they are dropped by the firewall.
|
||||
.Pp
|
||||
@ -472,37 +496,37 @@ After translation by
|
||||
packets re-enter the firewall at the rule number following the rule number
|
||||
that caused the diversion (not the next rule if there are several at the
|
||||
same number).
|
||||
|
||||
.It
|
||||
Enable your firewall by setting
|
||||
|
||||
firewall_enable=YES
|
||||
|
||||
.Pp
|
||||
.Dl firewall_enable=YES
|
||||
.Pp
|
||||
in
|
||||
.Pa /etc/rc.conf .
|
||||
This tells the system startup scripts to run the
|
||||
.Pa /etc/rc.firewall
|
||||
script. If you don't wish to reboot now, just run this by hand from the
|
||||
console. NEVER run this from a virtual session unless you put it into
|
||||
the background. If you do, you'll lock yourself out after the flush
|
||||
takes place, and execution of
|
||||
script.
|
||||
If you do not wish to reboot now, just run this by hand from the console.
|
||||
NEVER run this from a remote session unless you put it into the background.
|
||||
If you do, you will lock yourself out after the flush takes place, and
|
||||
execution of
|
||||
.Pa /etc/rc.firewall
|
||||
will stop at this point - blocking all accesses permanently. Running
|
||||
the script in the background should be enough to prevent this disaster.
|
||||
|
||||
will stop at this point - blocking all accesses permanently.
|
||||
Running the script in the background should be enough to prevent this
|
||||
disaster.
|
||||
.El
|
||||
|
||||
.Sh SEE ALSO
|
||||
.Xr socket 2 ,
|
||||
.Xr getservbyname 3 ,
|
||||
.Xr divert 4 ,
|
||||
.Xr protocols 5 ,
|
||||
.Xr rc.conf 5 ,
|
||||
.Xr services 5 ,
|
||||
.Xr ipfw 8
|
||||
|
||||
.Xr syslog.conf 5 ,
|
||||
.Xr ipfw 8 ,
|
||||
.Xr ppp 8 .
|
||||
.Sh AUTHORS
|
||||
This program is the result of the efforts of many people at different
|
||||
times:
|
||||
|
||||
.Pp
|
||||
.An Archie Cobbs Aq archie@whistle.com
|
||||
(divert sockets)
|
||||
.An Charles Mott Aq cmott@scientech.com
|
||||
|
||||
Loading…
Reference in New Issue
Block a user