From jono@biggins.securityreports.com Sun Jul 15 19:36:54 2001 Return-Path: Received: from biggins.securityreports.com (adsl-64-168-72-58.dsl.snfc21.pacbell.net [64.168.72.58]) by hub.freebsd.org (Postfix) with ESMTP id BA81C37B401 for ; Sun, 15 Jul 2001 19:36:51 -0700 (PDT) (envelope-from jono@biggins.securityreports.com) Received: (from root@localhost) by biggins.securityreports.com (8.11.4/8.11.1) id f6G2dk870176; Sun, 15 Jul 2001 19:39:46 -0700 (PDT) (envelope-from jono) Message-Id: <200107160239.f6G2dk870176@biggins.securityreports.com> Date: Sun, 15 Jul 2001 19:39:46 -0700 (PDT) From: jono@networkcommand.com Reply-To: jono@networkcommand.com To: FreeBSD-gnats-submit@freebsd.org Cc: jono@networkcommand.com Subject: New article for docproj "Checkpoint VPN-1/Firewall-1 and FreeBSD IPSEC" X-Send-Pr-Version: 3.113 X-GNATS-Notify: >Number: 28994 >Category: docs >Synopsis: New article for docproj "Checkpoint VPN-1/Firewall-1 and FreeBSD IPSEC" >Confidential: no >Severity: non-critical >Priority: low >Responsible: dd >State: closed >Quarter: >Keywords: >Date-Required: >Class: update >Submitter-Id: current-users >Arrival-Date: Sun Jul 15 19:40:01 PDT 2001 >Closed-Date: Mon Dec 23 14:39:36 PST 2002 >Last-Modified: Mon Dec 23 14:39:36 PST 2002 >Originator: Jon Orbeton >Release: FreeBSD 4.3-STABLE i386 >Organization: Security Reports >Environment: System: FreeBSD biggins.securityreports.com 4.3-STABLE FreeBSD 4.3-STABLE #8: Wed Jun 13 21:30:04 PDT 2001 root@biggins.securityreports.com:/usr/obj/usr/src/sys/BIGGINS i386 >Description: This is just an addition of a new article to the docproj. Please review and double-check my CVS id keywords, I wasn't clear on this. >How-To-Repeat: No repeat >Fix: %man; ]>
Integration of Checkpoint VPN-1/Firewall-1 and FreeBSD IPSEC Jon Orbeton
info@networkcommand.com
 Matt Hite
mhite@hotmail.com
 $Date$ 2001 Jon Orbeton &legalnotice; This document explains how to configure a VPN tunnel between FreeBSD and Checkpoint's VPN-1/Firewall-1. Other documents provide similar information, but do not contain instructions specific to VPN-1/Firewall-1 and its integration with FreeBSD. These documents are listed at the conclusion of this paper for further reference. Prerequisites The following is a diagram of the machines and networks referenced in this document. External Interface External Interface 208.229.100.6 216.218.197.2 | | +--> Firewall-1 <--> Internet <--> FreeBSD GW <--+ | | FW-1 Protected Nets Internal Nets 199.208.192.0/24 192.168.10.0/24 The FreeBSD GW serves as a firewall and NAT device for "internal nets." The FreeBSD kernel must be compiled to support IPSec. Use the following kernel options: options IPSEC options IPSEC_ESP options IPSEC_DEBUG For instructions on building a custom kernel, refer to the FreeBSD handbook. Please note that IP protocol 50 (ESP) and UDP port 500 must be open between the Firewall-1 host and the FreeBSD GW. Also, racoon must be installed to support key exchange. Racoon is part of the FreeBSD ports collection in /usr/ports/security/racoon. The racoon configuration file will be covered later in this document. Firewall-1 Network Object Configuration Begin by configuring the Firewall-1 Policy. Open the Policy Editor on the Firewall-1 Management server and create a new "Workstation" Network Object representing FreeBSD GW. General Tab: Set name and IP address VPN Tab: Encryption Schemes Defined: IKE ---> Edit IKE Properties: Key Negotiation Encryption Methods: 3DES Authenication Method: Pre-Shared Secret ---> Edit Select the Firewall Object and set a pre-shared secret. (Don't use our example.) Support Aggresive Mode: Checked Supports Subnets: Checked After setting the pre-shared secret in the Firewall-1 Network Object definition, place this secret in /usr/local/etc/racoon/psk.txt on FreeBSD GW. The format for psk.txt is: 208.229.100.6 rUac0wtoo? Firewall-1 VPN Rule Configuration Next, create a Firewall-1 rule enabling encryption between the FreeBSD GW and the Firewall-1 protected network. In this rule, the network services permitted through the VPN must be defined. Source | Destination | Service | Action | Track ------------------------------------------------------------------------ FreeBSD GW | FW-1 Protected Net | VPN services | Encrypt | Long FW-1 Protected Net| FreeBSD GW | | | "VPN services" are any services (i.e. telnet, ssh, ntp, etc.) remote hosts are permitted to access through the VPN. Use caution when permitting services; hosts connecting through a VPN still represent a potential security risk. Encrypting the traffic between the two networks offers little protection if a host on either side of the tunnel has been compromised. Once the rule specifying data encryption between the FreeBSD GW and the Firewall-1 protected network has been configured, review the "Action Encrypt" settings. Encryption Schemes Defined: IKE ---> Edit Transform: Encryption + Data Integrity (ESP) Encryption Algorithm: 3DES Data Integrity: MD5 Allowed Peer Gateway: Any or Firewall Object Use Perfect Forward Secrecy: Checked The use of Perfect Forward Secrecy (PFS) is optional. Enabling PFS will add another layer of encryption security, but does come at the cost of increased CPU overhead. If PFS is not used, uncheck the box above and comment out the pfs_group 1 line from racoon.conf on FreeBSD GW. An example racoon.conf is provided later in this document. FreeBSD VPN Policy Configuration At this point, the VPN policy on FreeBSD GW must be defined. The /usr/sbin/setkey tool performs this function. Below is an example shellscript which will flush setkey and add your VPN policy rules. # # /etc/vpn1-ipsec.sh # # IP addresses # # External Interface External Interface # 208.229.100.6 216.218.197.2 # | | # +--> Firewall-1 <--> Internet <--> FreeBSD GW <--+ # | | # FW-1 Protected Nets Internal Nets # 199.208.192.0/24 192.168.10.0/24 # # Flush the policy # setkey -FP setkey -F # # Configure the Policy # setkey -c << END spdadd 216.218.197.2/32 199.208.192.0/24 any -P out ipsec esp/tunnel/216.218.197.2-208.229.100.6/require; spdadd 199.208.192.0/24 216.218.197.2/32 any -P in ipsec esp/tunnel/208.229.100.6-216.218.197.2/require; END # Execute the setkey commands: &prompt.root; sh /etc/vpn1-ipsec.sh FreeBSD Racoon Configuration To facilitate the negotiation of IPSec keys on FreeBSD GW, /usr/ports/security/racoon must be installed and configured. The following is a racoon configuration file suitable for use with the examples outlined in this document. Please make sure you fully understand this file before using in a production environment. # racoon.conf for use with Checkpoint VPN-1/Firewall-1 # # search this file for pre_shared_key with various ID key. path pre_shared_key "/usr/local/etc/racoon/psk.txt" ; # # log debug; # # "padding" defines some parameter of padding. You should not touch these. padding { maximum_length 20; # maximum padding length. randomize off; # enable randomize length. strict_check off; # enable strict check. exclusive_tail off; # extract last one octet. } # listen { #isakmp ::1 [7000]; #isakmp 0.0.0.0 [500]; #admin [7002]; # administrative's port by kmpstat. #strict_address; # required all addresses must be bound. } # # Specification of default various timers. # timer { # These values can be changed per remote node. counter 5; # maximum trying count to send. interval 20 sec; # maximum interval to resend. persend 1; # the number of packets per a send. # # timer for waiting to complete each phase. phase1 30 sec; phase2 15 sec; } remote anonymous { exchange_mode aggressive,main; # For Firewall-1 Aggressive mode #my_identifier address; #my_identifier user_fqdn ""; #my_identifier address ""; #peers_identifier address ""; #certificate_type x509 "" ""; nonce_size 16; lifetime time 10 min; # sec,min,hour lifetime byte 5 MB; # B,KB,GB initial_contact on; support_mip6 on; proposal_check obey; # obey, strict or claim proposal { encryption_algorithm 3des; hash_algorithm md5; authentication_method pre_shared_key; dh_group 2 ; } } sainfo anonymous { pfs_group 1; lifetime time 10 min; lifetime byte 50000 KB; encryption_algorithm 3des; authentication_algorithm hmac_md5; compression_algorithm deflate ; } Ensure that /usr/local/etc/racoon/psk.txt contains the shared secret configured in the "Firewall-1 Network Object Configuration" section of this document and has mode 600 permissions. &prompt.root; chmod 600 /usr/local/etc/racoon/psk.txt Starting the VPN You are now ready to launch racoon and test the VPN tunnel. For debugging purposes, open the Firewall-1 Log Viewer and define a log filter to isolate entries pertaining to FreeBSD GW. You may also find it helpful to tail the racoon log: &prompt.root; tail -f /var/log/racoon.log Start racoon using the following command: &prompt.root; /usr/local/sbin/racoon -f /usr/local/etc/racoon/racoon.conf Once racoon has been launched, telnet to a host on the Firewall-1 protected network. &prompt.root; telnet -s 192.168.10.3 199.208.192.66 22 This command attempts to connect to the ssh port on 199.208.192.66, a machine in the Firewall-1 protected network. The -s switch indicates the source interface of the outbound connection. This is particularly important when running NAT and IPFW on FreeBSD GW. Using -s and specifying an explicit source address prevents NAT from mangling the packet prior to tunneling. A successful racoon key exchange will output the following to racoon.log: pfkey UPDATE succeeded: ESP/Tunnel 216.218.197.2->208.229.100.6 pk_recvupdate(): IPsec-SA established: ESP/Tunnel 216.218.197.2->208.229.100.6 get pfkey ADD message IPsec-SA established: ESP/Tunnel 208.229.100.6->216.218.197.2 Once key exchange completes (which takes a few seconds), an ssh banner will appear. If all went well, two "Key Install" messages will be logged in the Firewall-1 Log Viewer. Action | Source | Dest. | Info. Key Install | 216.218.197.2 | 208.229.100.6 | IKE Log: Phase 1 (aggressive) completion. Key Install | 216.218.197.2 | 208.229.100.6 | scheme: IKE methods Under the information column, the full log detail will read: IKE Log: Phase 1 (aggressive) completion. 3DES/MD5/Pre shared secrets Negotiation Id: scheme: IKE methods: Combined ESP: 3DES + MD5 + PFS (phase 2 completion) for host: References FreeBSD Handbook: IPSEC KAME Project FreeBSD IPSEC mini-HOWTO
>Release-Note: >Audit-Trail: From: Dima Dorfman To: jono@networkcommand.com Cc: FreeBSD-gnats-submit@freebsd.org Subject: Re: docs/28994: New article for docproj "Checkpoint VPN-1/Firewall-1 and FreeBSD IPSEC" Date: Thu, 19 Jul 2001 05:28:32 -0700 jono@networkcommand.com writes: Some very minor style/convention nits: > $Header$ This should be "$FreeBSD$". >
> > Integration of Checkpoint VPN-1/Firewall-1 and FreeBSD IPSEC Notice how you capitalized "IPSEC" here. > $Date$ This should also be "$FreeBSD$"; it may be a bit too much, but $Date$ wouldn't get expanded. > > External Interface External Interface > 208.229.100.6 216.218.197.2 > | | > +--> Firewall-1 <--> Internet <--> FreeBSD GW <--+ > | | > FW-1 Protected Nets Internal Nets > 199.208.192.0/24 192.168.10.0/24 > Things inside should cuddle up to the tags. Thus, the above should be written like this: External Interface External Interface 208.229.100.6 216.218.197.2 | | +--> Firewall-1 <--> Internet <--> FreeBSD GW <--+ | | FW-1 Protected Nets Internal Nets 199.208.192.0/24 192.168.10.0/24 There are some more violations of this below; I won't point them out explicitly, but you should fix them. > The FreeBSD GW serves as a firewall and NAT device for > "internal nets." How about: internal networks > > The FreeBSD kernel must be compiled to support IPSec. Remember how you capitalized "IPSEC" above? It'd be nice if they were the same. Personally I'd make them all "IPsec", but it's up to you. There are some other instances of this that should be fixed as well. > Also, racoon must be installed to support key exchange. "racoon" or "&man.racoon.1;", please (pick one). > 208.229.100.6 rUac0wtoo? > > > Extraneous whitespace. > ----------------------------------------------------------------------- > - > FreeBSD GW | FW-1 Protected Net | VPN services | Encrypt | Long > FW-1 Protected Net| FreeBSD GW | | | > > > "VPN services" are any services (i.e. telnet, ssh, ntp, etc.) VPN services.... Also, since you're referring to the protocols TELNET, SSH, NTP, etc. and not the commands, you should capitalize them. And if you were referring to protocols, you would mark them up inside . > At this point, the VPN policy on FreeBSD GW must be defined. The > /usr/sbin/setkey tool performs this function. "&man.setkey.1;", please. > Ensure that /usr/local/etc/racoon/psk.txt > contains the shared secret configured in the "Firewall-1 Network Object Firewall-1 Network Object Configuration > Configuration" section of this document and has mode 600 permissions. "600", please. > This command attempts to connect to the ssh port on 199.208.192.66, > a machine in the Firewall-1 protected network. The -s switch indicates "", please. > the source interface of the outbound connection. This is particularly important > when running NAT and IPFW on FreeBSD GW. Using -s and specifying an > explicit source address prevents NAT from mangling the packet prior to > tunneling. > > A successful racoon key exchange will output the following to racoon.log: Lines should be <= 80 characters in width (note that this does *not* apply to text inside or ). Overall, this is a *very* good article! I think it would be one of the most well-written ones in our tree. I'll gladly add it once you fix the above nits. Thanks, and nice work! Dima Dorfman dima@unixfreak.org State-Changed-From-To: open->feedback State-Changed-By: dd State-Changed-When: Sun Jul 29 02:56:57 PDT 2001 State-Changed-Why: Have you had a chance to do the updates yet? If not, that's okay, I'm just making sure you didn't accidently send it to the wrong address or something, and are thinking it's my turn to do something. Responsible-Changed-From-To: freebsd-doc->dd Responsible-Changed-By: dd Responsible-Changed-When: Sun Jul 29 02:56:57 PDT 2001 Responsible-Changed-Why: I'll look after this. http://www.FreeBSD.org/cgi/query-pr.cgi?pr=28994 State-Changed-From-To: feedback->closed State-Changed-By: trhodes State-Changed-When: Mon Dec 23 14:38:43 PST 2002 State-Changed-Why: Took comments from dd && marked up better. Then ran the entire thing through aspell. Finally, added a Makefile and committed! Thanks alot for the submission! http://www.freebsd.org/cgi/query-pr.cgi?pr=28994 >Unformatted: