Hi all,

I have a firewall running OpenBSD 4.1-STABLE with pptp-1.7.1 to access a
corporate VPN from a Windows XP machine on the internal LAN. The VPN uses
dial on demand. Running ping on the Windows machine to access the corporate
server (192.168.0.143) does connect the VPN but the pings timeout. After
some time, it varies from a few seconds to a minute or so the pings suddenly
start working. Meanwhile I can ping the same server directly from the
firewall over the VPN without any problem. 

Running tcpdump on ste1 and tun0 shows the following while pinging from the
XP machine when pings are not responding:

ste1 - 16:50:12.591916 192.168.11.11 > 192.168.0.143: icmp: echo request
tun0 - 16:50:12.591994 192.168.3.1 > 192.168.0.143: icmp: echo request

While pings are still failing from XP pinging the same server from the
firewall shows:

tun0 - 16:50:34.424287 192.168.3.202 > 192.168.0.143: icmp: echo request
tun0 - 16:50:34.483484 192.168.0.143 > 192.168.3.202: icmp: echo reply

When the XP machine is finally able to ping the server I get:

ste1 - 16:50:51.508714 192.168.11.11 > 192.168.0.143: icmp: echo request
tun0 - 16:50:51.508787 192.168.3.202 > 192.168.0.143: icmp: echo request
tun0 - 16:50:51.560419 192.168.0.143 > 192.168.3.202: icmp: echo reply
ste1 - 16:50:51.560463 192.168.0.143 > 192.168.11.11: icmp: echo reply

The address on tun0 changes from 192.168.3.1 when pings fail to
192.168.3.202 when they work. It looks like ($vpn_if) is taking too long to
change to the new address (192.168.3.202) from the one in ifaddr
(192.168.3.1).

How do I get the VPN to connect and be usable immediately from the Windows
XP machine without this delay?

TIA
Paul

------------------------------------------------------------------------

pf.conf
-------
ext_if="vr0"
lan_if="ste1"
vpn_if="tun0"

set skip on lo

nat on $ext_if from $lan_if:network to any -> $ext_if
nat on $vpn_if from $lan_if:network to any -> ($vpn_if)

block in quick inet6 all
block out quick inet6 all

block in log all
block out log all

pass in quick on $lan_if inet from $lan_if:network to any flags S/SA

pass out quick on $ext_if inet from $ext_if to any flags S/SA modulate state
pass out quick on $vpn_if inet to any flags S/SA modulate state

------------------------------------------------------------------------

ppp.conf
--------
default:
 set log Phase Chat LCP IPCP CCP tun command

vpn:
 set device "!/usr/local/sbin/pptp --nolaunchpppd xx.xx.xx.xx"
 set authname xxxxxxxx
 set authkey xxxxxxxx
 set mppe 128 stateless
 set ifaddr 192.168.3.1/0 192.168.3.2/0 255.255.255.0 0.0.0.0
 add 192.168.0.0 255.255.255.0 192.168.3.2
 add 192.168.3.0 255.255.255.0 192.168.3.2

------------------------------------------------------------------------

(spamassassinexception)

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