diff options
Diffstat (limited to 'usr.sbin/authpf/authpf.8')
| -rw-r--r-- | usr.sbin/authpf/authpf.8 | 74 |
1 files changed, 53 insertions, 21 deletions
diff --git a/usr.sbin/authpf/authpf.8 b/usr.sbin/authpf/authpf.8 index 141aecf7d6a..b6977da2fce 100644 --- a/usr.sbin/authpf/authpf.8 +++ b/usr.sbin/authpf/authpf.8 @@ -1,4 +1,4 @@ -.\" $OpenBSD: authpf.8,v 1.30 2003/08/17 23:24:47 henning Exp $ +.\" $OpenBSD: authpf.8,v 1.31 2003/12/10 04:10:37 beck Exp $ .\" .\" Copyright (c) 2002 Bob Beck (beck@openbsd.org>. All rights reserved. .\" @@ -84,9 +84,9 @@ shared by all processes. By default, the .Pa anchor -name "authpf" is used, and the ruleset names equal the PIDs of the +name "authpf" is used, and the ruleset names equal the username and PID of the .Nm -processes. +processes as "username(pid)". The following rules need to be added to the main ruleset .Pa /etc/pf.conf in order to cause evaluation of any @@ -263,7 +263,8 @@ by creating an appropriate .Pa /etc/authpf/authpf.conf file. .Sh EXAMPLES -\fBControl Files\fP - To illustrate the user-specific access control +.Sy Control Files +\- To illustrate the user-specific access control mechanisms, let us consider a typical user named bob. Normally, as long as bob can authenticate himself, the .Nm @@ -298,7 +299,8 @@ file. Though bob is listed in the allow file, he is prevented from using this gateway due to the existence of a ban file. .Pp -\fBDistributed Authentication\fP - It is often desirable to interface with a +.Sy Distributed Authentication +\- It is often desirable to interface with a distributed password system rather than forcing the sysadmins to keep a large number of local password files in sync. The @@ -332,7 +334,8 @@ Using a default password file, all users will get as their shell except for root who will get .Pa /bin/csh . .Pp -\fBSSH Configuration\fP - As stated earlier, +.Sy SSH Configuration +\- As stated earlier, .Xr sshd 8 must be properly configured to detect and defeat network attacks. To that end, the following options should be added to @@ -346,7 +349,8 @@ ClientAliveCountMax 3 This ensures that unresponsive or spoofed sessions are terminated within a minute, since a hijacker should not be able to spoof ssh keepalive messages. .Pp -\fBBanners\fP - Once authenticated, the user is shown the contents of +.Sy Banners +\- Once authenticated, the user is shown the contents of .Pa /etc/authpf/authpf.message . This message may be a screen-full of the appropriate use policy, the contents of @@ -366,7 +370,8 @@ problem so we can fix it, please phone 1-900-314-1597 or send an email to remove@bulkmailerz.net. .Ed .Pp -\fBPacket Filter Rules\fP - In areas where this gateway is used to protect a +.Sy Packet Filter Rules +\- In areas where this gateway is used to protect a wireless network (a hub with several hundred ports), the default rule set as well as the per-user rules should probably allow very few things beyond encrypted protocols like @@ -378,15 +383,14 @@ On a securely switched network, with plug-in jacks for visitors who are given authentication accounts, you might want to allow out everything. In this context, a secure switch is one that tries to prevent address table overflow attacks. -The examples below assume a switched wired net. .Pp Example .Pa /etc/pf.conf : .Bd -literal # by default we allow internal clients to talk to us using # ssh and use us as a dns server. -internal_if=\&"fxp1\&" -gateway_addr=\&"10.0.1.1\&" +internal_if="fxp1" +gateway_addr="10.0.1.1" nat-anchor authpf rdr-anchor authpf binat-anchor authpf @@ -398,26 +402,28 @@ pass in quick on $internal_if proto udp from any to $gateway_addr \e anchor authpf .Ed .Pp -Example -.Pa /etc/authpf/authpf.rules : +.Sy For a switched, wired net +\- This example +.Pa /etc/authpf/authpf.rules +makes no real restrictions; it turns the IP address on and off, logging +TCP connections. .Bd -literal -# no real restrictions here, basically turn the network jack off or on. - -external_if = \&"xl0\&" -internal_if = \&"fxp0\&" +external_if = "xl0" +internal_if = "fxp0" pass in log quick on $internal_if proto tcp from $user_ip to any \e keep state pass in quick on $internal_if from $user_ip to any .Ed .Pp -Another example +.Sy For a wireless or shared net +\- This example .Pa /etc/authpf/authpf.rules -for an insecure network (such as a public wireless network) where +could be used for an insecure network (such as a public wireless network) where we might need to be a bit more restrictive. .Bd -literal -internal_if=\&"fxp1\&" -ipsec_gw=\&"10.2.3.4\&" +internal_if="fxp1" +ipsec_gw="10.2.3.4" # rdr ftp for proxying by ftp-proxy(8) rdr on $internal_if proto tcp from $user_ip to any port 21 \e @@ -433,6 +439,32 @@ pass in quick proto udp from $user_ip to $ipsec_gw port = isakmp \e keep state pass in quick proto esp from $user_ip to $ipsec_gw .Ed +.Pp +.Sy Dealing with NAT +\- The following +.Pa /etc/authpf/authpf.rules +shows how to deal with NAT, using tags: +.Bd -literal +ext_if = "fxp1" +ext_addr = 129.128.11.10 +int_if = "fxp0" +# nat and tag connections... +nat on $ext_if from $user_ip to any tag $user_ip -> $ext_addr +pass in quick on $int_if from $user_ip to any +pass out log quick on $ext_if tagged $user_ip keep state +.Ed +.Pp +With the above rules added by +.Nm , +outbound connections corresponding to each users NAT'ed connections +will be logged as in the example below, where the user may be identified +from the ruleset name. +.Bd -literal +# tcpdump -n -e -ttt -i pflog0 +Oct 31 19:42:30.296553 rule 0.bbeck(20267).1/0(match): pass out on fxp1: \e +129.128.11.10.60539 > 198.137.240.92.22: S 2131494121:2131494121(0) win \e +16384 <mss 1460,nop,nop,sackOK> (DF) +.Ed .Sh FILES .Bl -tag -width "/etc/authpf/authpf.conf" -compact .It Pa /etc/authpf/authpf.conf |