Re: OpenBSD VPN

From: Peter Grießl (griesslihs.ac.at)
Date: Thu Feb 17 2005 – 02:29:22 CST

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——————————————————————————–

Mark Maxey wrote:

>
> My incoming hosts will be a mixture of Windows XP/2000 and Linux
> clients, but knowledgeable users. Preferably this solution would be
> able to use a free client or use the ipsec/vpn capabilities built into
> MS windows.
>

Hi Mark,
use IPsec – Windows 2000/XP has builtin support for IPsec, no need for any
extra client software.
The only magic is the configuration; in theory one can configure IPsec
using clicksy graphical interfaces (Management Console …), practically
you cannot. But tunnel setup is perfectly possible using a simple
batch file and the MS tools ipsecpol.exe (W2k) or ipseccmd.exe (XP).

for certificates, we use http://www.klake.org/~jt/mkca

The clients only need to install the *.p12 certificate file (double-click
installation does not work, you have to go through MMC – Certificate SnapIn
– right-click Personal – All Tasks – Import – Wizard – browse to the *.p12
file – password – change the certificate store to “Automatically select
the certificate store based on the type of certificate” – next – complete –
finish

XPSP2: start testing with firewall disabled (note: tunnel works ok with
firewall enabled, only problems using icmp – XPSP2-bug)

Personal Firewalls (Norton, McAfee): some work together with IPsec, some
don’t (some have to be completely deinstalled to make IPsec work, disabling
does not help)

Users must have administrative rights to set up the IPsec-tunnel on 2000/XP.

So, here are the batchfiles we use:

START_VPN.BAT (call with Samba-username and Samba-password as arguments)
————-

echo off
set VPNPATH=c:ihsvpn
title please wait …

rem we have two ipsec gateways, one batchfile
set WLANGW=143.130.40.1
set DMZGW=143.130.36.2
set USER=%1
set PASS=%2

rem 2000 or XP ?

ver | findstr 2000
if not errorlevel 1 goto 2000
ver | findstr XP
if not errorlevel 1 goto XP
goto OUT
:2000
set TOOL=ipsecpol
goto OSOK
:XP
set TOOL=ipseccmd
:OSOK

rem disable and delete old ipsec policy (sometimes required,
rem user did not call stop_vpn.bat last time)

%VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2LAN -y
%VPNPATH%%TOOL% -w REG -p IHSVPN -r LAN2NB -y
%VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2DHCP -y
%VPNPATH%%TOOL% -w REG -p IHSVPN -r DHCP2NB -y
%VPNPATH%%TOOL% -w REG -p IHSVPN -o

rem Which gateway is accessible?

ping -n 3 %WLANGW% | find “TTL” > NUL
if not errorlevel 1 goto WLAN
ping -n 3 %DMZGW% | find “TTL” > NUL
if not errorlevel 1 goto DMZ
goto EXIT
:WLAN
set IPSECGW=%WLANGW%
goto DOIT
:DMZ
set IPSECGW=%DMZGW%
:DOIT

REM all traffic to our net should go through the ipsec tunnel

set ROUTE=143.130.32.0/255.255.240.0

REM find client’s ip address

set ipaddr=
for /F “tokens=2 delims=:” %%f in (‘ipconfig ^| findstr dress’) do set
ipaddr=%%f
if “%ipaddr%”==”” goto EXIT
REM trim space
set ipaddr=%ipaddr:~1%

REM DHCP-server?

set dhcp=
for /F “tokens=2 delims=:” %%f in (‘ipconfig /all ^| findstr /C:”DHCP
Server”‘) do set dhcp=%%f
REM trim space
set dhcp=%dhcp:~1%

REM create IPSEC policy and activate tunnel

%VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2LAN -t %ipsecgw% -f 0=%ROUTE% -n
ESP[SHA,3DES]P -a CERT:”C=AT, S=Austria, L=Vienna, O=Institute for Advanced
Studies, OU=IHS, CN=Institute for Advanced Studies”
%VPNPATH%%TOOL% -w REG -p IHSVPN -r LAN2NB -t %ipaddr% -f %ROUTE%=0 -n
ESP[SHA,3DES]P -a CERT:”C=AT, S=Austria, L=Vienna, O=Institute for Advanced
Studies, OU=IHS, CN=Institute for Advanced Studies”
if %dhcp%==~1 goto activate
%VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2DHCP -t %ipsecgw% -f
0:68=%dhcp%:67:UDP -n PASS
%VPNPATH%%TOOL% -w REG -p IHSVPN -r DHCP2NB -t %ipaddr% -f
%dhcp%:67=0:68:UDP -n PASS
:activate
%VPNPATH%%TOOL% -w REG -p IHSVPN -x

REM negotiate and check IPSEC

rem ping the samba server to setup and check the ipsec tunnel
ping -n 4 143.130.45.10 < ======= doesn't work with XPSP2 FW enabled nbtstat -A 143.130.45.10 ping -n 2 143.130.45.10 | find "TTL" <======= ................ if not errorlevel 1 goto MOUNT %VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2LAN -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r LAN2NB -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2DHCP -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r DHCP2NB -y %VPNPATH%%TOOL% -w REG -p IHSVPN -o goto EXIT REM mount network drives (if you need this) :MOUNT rem mount your samba shares (net use .... %USER% %PASS%) goto OUT :EXIT echo Something went wrong, sorry! :OUT exit STOP_VPN.BAT ------------ echo off set VPNPATH=c:ihsvpn title please wait ... rem unmount samba shares rem net use .... /d rem 2000 or XP ? ver | findstr 2000 if not errorlevel 1 goto 2000 ver | findstr XP if not errorlevel 1 goto XP goto EXIT :2000 set TOOL=ipsecpol goto OSOK :XP set TOOL=ipseccmd :OSOK rem disable and delete ipsec policy %VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2LAN -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r LAN2NB -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r NB2DHCP -y %VPNPATH%%TOOL% -w REG -p IHSVPN -r DHCP2NB -y %VPNPATH%%TOOL% -w REG -p IHSVPN -o :EXIT exit here are the OpenBSDs (3.6) config files: /etc/isakmpd/isakmpd.conf # --- Global options [General] Retransmits= 5 Exchange-max-time= 120 Listen-on= 143.130.40.1 Shared-SADB= Defined Renegotiate-on-HUP= Defined # --- X.509 certificate locations [X509-certificates] CA-directory= /etc/isakmpd/ca/ Cert-directory= /etc/isakmpd/certs/ Private-key= /etc/isakmpd/private/local.key # --- IKE Phase 1 & 2 [Phase 1] Default= Client-phase1 [Phase 2] Passive-Connections= Client-phase2 [Client-phase1] Phase= 1 Transport= udp Local-address= 143.130.40.1 Configuration= Default-main-mode ID= My-ID [My-ID] ID-type= FQDN Name= ipsecgw.ihs.ac.at [Client-phase2] Phase= 2 ISAKMP-peer= Client-phase1 Local-ID= All-networks Remote-ID= Unknown-address # --- Network details [All-networks] ID-Type= IPV4_ADDR_SUBNET Network= 0.0.0.0 Netmask= 0.0.0.0 [Unknown-address] ID-Type= IPV4_ADDR Address= 0.0.0.0 # --- Main and quick mode transforms [Default-main-mode] DOI= IPSEC EXCHANGE_TYPE= ID_PROT Transforms= 3DES-SHA-RSA_SIG [3DES-SHA-RSA_SIG] ENCRYPTION_ALGORITHM= 3DES_CBC HASH_ALGORITHM= SHA AUTHENTICATION_METHOD= RSA_SIG AUTHENTICATION_ALGORITHM= HMAC_SHA Life= Phase1-Lifetime [Phase1-Lifetime] LIFE_TYPE= SECONDS LIFE_DURATION= 3600,60:86400 /etc/isakmpd/isakmpd.policy KeyNote-Version: 2 Authorizer: "POLICY" Licensees: "DN:/C=AT/ST=Austria/L=Vienna/O=Institute for Advanced Studies/OU=IHS/CN=Institute for Advanced Studies" Conditions: app_domain == "IPsec policy" && esp_present == "yes" && remote_id_type == "ASN1 DN" && esp_enc_alg != "null" -> “true”;

Hope that helps!
Greetings from cold Vienna,
Peter Griessl, griesslihs.ac.at