Sponsored Content
Full Discussion: fBSD nat ipfw
Top Forums UNIX for Dummies Questions & Answers fBSD nat ipfw Post 22667 by eNTer on Friday 7th of June 2002 03:20:19 PM
Old 06-07-2002
look at this example, i can asure you it's working, is a modification made to the default /etc/rc.firewall :
Code:
[Ss][Ii][Mm][Pp][Ll][Ee])
        ############
        # This is a prototype setup for a simple firewall.  Configure this
        # machine as a named server and ntp server, and point all the machines
        # on the inside at this machine for those services.
        ############

        dont_deny="my_very_best_friend"

        # set these to your outside interface network and netmask and ip
        oif="rl1"
        onet="outside_net_address"
        omask="255.255.255.240"
        oip="outside_ip_addr"

        # set these to your inside interface network and netmask and ip
        iif="rl0"
        inet="internal_net_address"
        imask="255.255.255.0"
        iip="internal_ip"

        # Stop spoofing
        ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif}
        ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif}

        # Stop RFC1918 nets on the outside interface
        ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif}
        ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif}
        ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif}

        # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
        # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
        # on the outside interface
        ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif}
        ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif}
        ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif}
        ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif}
        ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif}


        #########       RULES BEFORE NAT      ######################

        # Allow access for iserver
        #${fwcmd} add pass tcp from 192.168.10.10 to any out setup
        # Allow access for SIMM-3
        #${fwcmd} add pass tcp from 192.168.10.20 to any out setup
        # Deny everything else
        #${fwcmd} add deny all from 192.168.0.0/24 to any setup
        #

        #######################################################################

        # Network Address Translation.  This rule is placed here deliberately
        # so that it does not interfere with the surrounding address-checking
        # rules.  If for example one of your internal LAN machines had its IP
        # address set to 192.0.2.1 then an incoming packet for it after being
        # translated by natd(8) would match the `deny' rule above.  Similarly
        # an outgoing packet originated from it before being translated would
        # match the `deny' rule below.
        case ${natd_enable} in
        [Yy][Ee][Ss])
                if [ -n "${natd_interface}" ]; then
                        ${fwcmd} add divert natd all from any to any via ${natd_interface}
                fi
                ;;
        esac

        # Stop RFC1918 nets on the outside interface
        ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif}
        ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif}
        ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif}

        # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1,
        # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E)
        # on the outside interface
        ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif}
        ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif}
        ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif}
        ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif}
        ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif}

        ####    RULES AFTER NAT       ##########################

        ${fwcmd} add pass tcp from any to me 113
        ${fwcmd} add pass tcp from me 113 to any

        # ${fwcmd} add pass tcp from me to any via ${iif} keep-state

        ##################################################################

        # Don't deny address[es]
        ${fwcmd} add pass all from ${dont_deny} to any
        ${fwcmd} add pass all from any to ${dont_deny}

        # Allow TCP through if setup succeeded
        ${fwcmd} add pass tcp from any to any established

        # Allow IP fragments to pass through
        ${fwcmd} add pass all from any to any frag

        # Allow setup of incoming email
        ${fwcmd} add pass tcp from any to ${oip} 25 setup

        # Allow access to our DNS
        ${fwcmd} add pass tcp from any to ${oip} 53 setup
        ${fwcmd} add pass udp from any to ${oip} 53
        ${fwcmd} add pass udp from ${oip} 53 to any

        # Allow access to our WWW
        ${fwcmd} add pass tcp from any to ${oip} 80 setup

        # Allow access to Webmin
        ${fwcmd} add pass tcp from any to ${oip} 3129 setup

        # SSH
        ${fwcmd} add pass tcp from any to ${oip} 22 setup

        # FTP
        ${fwcmd} add pass tcp from any to ${oip} 21 setup

        # FTP-data
        ${fwcmd} add pass tcp from any to ${oip} 20 setup

        # SMTP
        ${fwcmd} add pass tcp from any to ${oip} 25 setup

        # POP3
        ${fwcmd} add pass tcp from any to ${oip} 110 setup

        # Reject&Log all setup of incoming connections from the outside
        ${fwcmd} add deny log tcp from any to any in via ${oif} setup

        # Allow setup of any other TCP connection
        ${fwcmd} add pass tcp from any to any setup

        # Allow DNS queries out in the world
        ${fwcmd} add pass udp from ${oip} to any 53 keep-state

        # Allow NTP queries out in the world
        ${fwcmd} add pass udp from ${oip} to any 123 keep-state

        # Everything else is denied by default, unless the
        # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
        # config file.
        ;;

added code tags for readability --oombera

Last edited by oombera; 02-18-2004 at 12:57 PM..
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

my fbsd gateway

hi i got a problem. I use a fbsd box to share my (DSL)internet connection. I got 2 networkcards in my fbsd box, but my networkcard 1 (to my modem) always go out. the led don't burn anymore and I lose my connection to the internet :( but my networkcard2 (to my local network) doesn't go out,... (2 Replies)
Discussion started by: Stormpie
2 Replies

2. UNIX for Dummies Questions & Answers

C-Media 8738 chipset for FBSD 4.4

HI i'm compiling my kernel with the support of this chipset. In FreeBSD 4.2 and 4.3 I got no problem with the kernel, but with 4.4 I just can't get the kernel compiled with the soundcard support. i added this to my kernel device pcm device snd something wrong... (2 Replies)
Discussion started by: Stormpie
2 Replies

3. UNIX for Dummies Questions & Answers

Color konsole in FBSD 4.6

FBSD 4.6 How do I colorize my konsole to see directories etc. Am able to get color in the shell with ls -GF in my .bashrc. But color does not show in KDE3 Konsole (Xwindows) for some reason.FBSD 4.6 (1 Reply)
Discussion started by: lancest
1 Replies

4. Cybersecurity

ipfw directives and order of precidence...

Is there a general rule I can apply when examining/editing ipfw entries? Also, does each new entry have to have a unique rule number? And, I think I can write a script to block code red infected machines (though I'm not sure it would do more than slim down my web server error message log),... (0 Replies)
Discussion started by: [MA]Flying_Meat
0 Replies

5. BSD

Casio CASSIOPEA BE-300 & fBSD

I just don't know how do I have to connect them... Connecting via USB, if some body knows, please post here... Thankue... (0 Replies)
Discussion started by: PomaH 6yxDAK
0 Replies

6. UNIX for Dummies Questions & Answers

Need help with IPFW.. Please...

Hi folks, I am a Mac User, and have little knowledge on IPFW. I have a set up at home where my computer (with 2 ethernet cards and static IP adresses) serves Internet to my family's computers. I have already a script that will run automatically at login and called from Cron at certain... (2 Replies)
Discussion started by: fundidor
2 Replies

7. UNIX for Advanced & Expert Users

FBSD jail question

I'm trying to establish a jail on a FBSD 6.1 system and have a couple of questions on bringing up the daemon. Under the jail man page there are two user flags that I am unclear on, -u username The user name from host environment as whom the command should run. -U... (1 Reply)
Discussion started by: thumper
1 Replies

8. BSD

Using several pipes in ipfw (dummynet)

Hi! I've already posted this on the freebsd-questions mailing list, but I thought I could try it here too. I'm using FreeBSD 7.0 with IPFW DUMMYNET enabled. I've got a problem with creating a ruleset, which allows me to limit the overall bandwidth of a link and afterwards pass the packets... (0 Replies)
Discussion started by: xenator
0 Replies

9. UNIX for Advanced & Expert Users

ipfw and dhcp

Hello, I have a little problem with my server configuration. So: I have two PC's with DHCP enable and both of them have two NIC's. PC1 - le0 ADSL PC1 - le1 192.168.10.1 PC2 - le0 192.168.10.10 PC2 - le1 192.168.20.1 One NIC on PC1 is connected to ADSL, another one have IP address... (3 Replies)
Discussion started by: mrowcp
3 Replies

10. OS X (Apple)

How to enable ipfw.log?

Under Mountain Lion, I want logs from ipfw sent to ipfw.log instead of dumped in system.log I've tried to figure out how OSX handles logs, but... after going back and forth between a syslog.conf which does little if anything, a newsyslog.conf that seems to only handle rotation, an asl.conf that... (3 Replies)
Discussion started by: jnojr
3 Replies
All times are GMT -4. The time now is 09:20 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy