VPN problem

[Mario Lobo]

Hi;

I've been having this problem closing a VPN behind a FreeBSD 8-STABLE with pf.

I have this scenario:

home LAN ---- FBSD+pf home ---- INTERNET --- FBSD+pf work --- work LAN
                                             MPD VPN server

 nat on $ext_if from $int_if:network to any -> ($ext_if) port 1024:65535
 # nat on $ext_if from any to any -> ($ext_if) port 1024:65535

obs- it makes no difference which nat rule I use. The problem persists.

These are the first 5 pf rules on FBSD+pf home:

  # pass quick all
  pass quick on lo0 all

  # my whole home lan is free
  pass in quick on $int_if from $int_if:network to any
  
  #--- Allow networks to see themselves and dns
  pass quick from $int_if:network to $int_if:network
  
  #--- Allow vpns from anywhere to anywhere
  pass in quick log on $int_if proto gre from any to any keep state
  pass in quick log on $int_if proto tcp from any to any port pptp flags S/SA 
keep state



On any attempt to conect to the FBSD+pf work VPN Server from home LAN, 
I get this (even if I uncomment  pass quick all):

#>mpd5
Multi-link PPP daemon for FreeBSD
 
process 98799 started, version 5.5 (root at Papi 16:55  3-Sep-2011)
CONSOLE: listening on 127.0.0.1 5005
web: listening on 127.0.0.1 5006
[B1] Bundle: Interface ng0 created
[L1] [L1] Link: OPEN event
[L1] LCP: Open event
[L1] LCP: state change Initial --> Starting
[L1] LCP: LayerStart
[L1] PPTP call successful
[L1] Link: UP event
[L1] LCP: Up event
[L1] LCP: state change Starting --> Req-Sent
[L1] LCP: SendConfigReq #1
[L1]   ACFCOMP
[L1]   PROTOCOMP
[L1]   ACCMAP 0x000a0000
[L1]   MRU 1486
[L1]   MAGICNUM 2d08ae01

[snip..]

[L1] LCP: SendConfigReq #10
[L1]   ACFCOMP
[L1]   PROTOCOMP
[L1]   ACCMAP 0x000a0000
[L1]   MRU 1486
[L1]   MAGICNUM 2d08ae01
[L1] LCP: parameter negotiation failed
[L1] LCP: state change Req-Sent --> Stopped
[L1] LCP: LayerFinish
[L1] PPTP call terminated
[L1] Link: DOWN event
[L1] LCP: Close event
[L1] LCP: state change Stopped --> Closed
[L1] LCP: Down event
[L1] LCP: state change Closed --> Initial

BUT, on the 9th or 10th attempt, without touching any setting anywhere, the 
VPN MAY BE established. out of nothing ! Machines (Windows, unix, whatever) 
behind both FBSD+pfs ALSO have the same problem when trying to close VPN 
tunnels to outside sites.

The FBSD+pf work VPN Server is working fine. My coleagues can conect to it 
from their homes (NATted cable modems or 3G modems) without problems. I am the 
only one behind a FBSD+pf router. 

I installed MPD5 on FBSD+pf home, and copied mpd.conf from my home workstation 
to it. 

Without touching a single setting on mpd.conf, the VPN is established 
from FBSD+pf home (as a client) to FBSD+pf work WITHOUT any hickups on EVERY 
SINGLE attempt! even I bring it up/down 200 times!


And yet, if the FBSD+pf combo is out of the way, (i.e. no NAT!, as is the case 
of FBSD+pf home as a client) or if I let my cable modem do the NAT/routing, 
the problem is GONE!.

FreeBSD work 
FreeBSD 8.2-STABLE #0: Mon Aug 22 14:50:42 BRT 2011 amd64

FreeBSD Home
FreeBSD FreeBSD 8.2-STABLE #0: Wed May 18 16:53:26 BRT 2011 i386

Any suggestions?

-- 
Mario Lobo
http://www.mallavoodoo.com.br
FreeBSD since 2.2.8 [not Pro-Audio.... YET!!] (99% winblows FREE)