Ситуация такая , есть роутер FreeBSD 6.4 на нем поднят MPD5(как сервер VPN) + в другом городе есть роутер LinuxSuse 10 на нем поднят pptp клиент для MPD.
Все отлично коннектиться vpn канал создается принги от Linux до FreeBSD ходят. От клиентских машин за Linux до клиентских машин за FreeBSD ходят. А вот от клиентской тачки за FreeBSD до Линухового клиента НЕТ.
Ifconfig:linux
eth0      Link encap:Ethernet  HWaddr 00:18:71:E3:40:31
          inet addr:10.205.250.1  Bcast:10.205.250.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:179562394 errors:0 dropped:0 overruns:0 frame:0
          TX packets:148058322 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:2019135156 (1925.5 Mb)  TX bytes:1454938935 (1387.5 Mb)
          Interrupt:233

eth1      Link encap:Ethernet  HWaddr 00:18:71:E3:40:30
          inet addr:X.X.X.X  Bcast:X.X.X.X  Mask:255.255.255.248
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:56957221 errors:0 dropped:0 overruns:0 frame:0
          TX packets:54195159 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1557769638 (1485.6 Mb)  TX bytes:435429409 (415.2 Mb)
          Interrupt:50

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:11738708 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11738708 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:1804942600 (1721.3 Mb)  TX bytes:1804942600 (1721.3 Mb)

ppp0      Link encap:Point-to-Point Protocol
          inet addr:10.50.4.210  P-t-P:10.50.4.201  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
          RX packets:1574 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1240 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:97156 (94.8 Kb)  TX bytes:74278 (72.5 Kb)

Ifconfig:FreeBSD
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=1b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
        inet 10.50.0.251 netmask 0xffff0000 broadcast 10.50.255.255
        ether 00:0c:29:d8:fc:73
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=1b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
        inet 192.168.2.2 netmask 0xffffff00 broadcast 192.168.2.255
        ether 00:0c:29:d8:fc:7d
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active
plip0: flags=108810<POINTOPOINT,SIMPLEX,MULTICAST,NEEDSGIANT> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x4
        inet6 ::1 prefixlen 128
        inet 127.0.0.1 netmask 0xff000000
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> mtu 1458
        inet 10.50.4.201 --> 10.50.4.210 netmask 0xffffffff

IPFW:linux
FW_DEV_EXT="any eth-id-00:11:75:e3:43:30"
FW_DEV_INT="eth-id-00:18:63:e3:34:39"
FW_DEV_DMZ=""

FW_ROUTE="yes"

FW_MASQUERADE="yes"

FW_MASQ_DEV="$FW_DEV_EXT"

#FW_MASQ_NETS="0/0"
FW_MASQ_NETS="\
10.50.0.0/16,10.205.250.0/24,icmp \
10.205.250.252/32,0/0,tcp,25 \
10.205.250.196/32,0/0,tcp,443 \
10.205.250.0/24,X.X.X.X/24,tcp,53 \
10.205.250.0/24,X.X.X.X/24,udp,53 \
10.205.250.0/24,0/0,gre \
10.50.0.0/16,0/0,gre \
10.205.250.7/32,0/0,icmp \
10.205.250.157/32,0/0,icmp \
10.205.250.0/24,X.X.X.X/32,tcp,2226"

FW_PROTECT_FROM_INT="no"
FW_SERVICES_EXT_TCP="https smtp ssh 1723"
FW_SERVICES_EXT_UDP=""
FW_SERVICES_EXT_IP="gre"
FW_SERVICES_EXT_RPC=""
FW_CONFIGURATIONS_EXT=""

FW_SERVICES_DMZ_TCP=""
FW_SERVICES_DMZ_UDP=""
FW_SERVICES_DMZ_IP="gre"
FW_SERVICES_DMZ_RPC=""
FW_CONFIGURATIONS_DMZ=""

FW_SERVICES_INT_TCP=""
FW_SERVICES_INT_UDP=""
FW_SERVICES_INT_IP="gre"
FW_SERVICES_INT_RPC=""
FW_CONFIGURATIONS_INT=""

FW_SERVICES_DROP_EXT=""

#FW_SERVICES_REJECT_EXT="0/0,tcp,113"

FW_SERVICES_ACCEPT_EXT=""

FW_TRUSTED_NETS="\
10.205.250.0/24 \
10.50.0.0/16"

FW_ALLOW_INCOMING_HIGHPORTS_UDP=""

FW_FORWARD=""

FW_FORWARD_MASQ="X.X.X.X/32,10.205.250.5,tcp,3395,3389,X.X.X.X"

FW_REDIRECT="\
10.205.250.0/24,0/0,tcp,80,3128 \
10.205.250.0/24,0/0,tcp,8080,3128"

FW_LOG_ACCEPT_CRIT="yes"
FW_LOG_ACCEPT_ALL="no"
FW_LOG_LIMIT=""
FW_LOG=""

FW_KERNEL_SECURITY="yes"

FW_STOP_KEEP_ROUTING_STATE="no"

FW_ALLOW_PING_FW="no"
FW_ALLOW_PING_DMZ="no"
FW_ALLOW_PING_EXT="no"

#-------------------------------------------------------------------------#
# EXPERT OPTIONS - all others please don't change these!                  #
#-------------------------------------------------------------------------#
FW_ALLOW_FW_SOURCEQUENCH=""
FW_ALLOW_FW_BROADCAST_EXT="no"
FW_ALLOW_FW_BROADCAST_INT="no"
FW_ALLOW_FW_BROADCAST_DMZ="no"
FW_IGNORE_FW_BROADCAST_EXT="yes"
FW_IGNORE_FW_BROADCAST_INT="no"
FW_IGNORE_FW_BROADCAST_DMZ="no"
FW_ALLOW_CLASS_ROUTING=""
FW_CUSTOMRULES=""
FW_REJECT=""
FW_REJECT_INT="yes"
FW_HTB_TUNE_DEV=""
FW_IPv6=""
FW_IPv6_REJECT_OUTGOING=""
FW_IPSEC_TRUST="no"
FW_ZONES=""
FW_USE_IPTABLES_BATCH=""
FW_LOAD_MODULES=""
FW_FORWARD_ALWAYS_INOUT_DEV="xenbr0"
FW_SERVICES_ACCEPT_INT=""
FW_SERVICES_ACCEPT_DMZ=""
FW_LOG_DROP_CRIT="yes"
FW_LOG_DROP_ALL="no"

IPFW:FreeBSD
00100   626948   191198486 allow ip from 10.26.0.0/16 to 10.16.0.0/16
00102     6346      388960 allow ip from 10.50.0.0/16 to 10.205.250.0/24
00102     5072      304320 allow ip from 10.205.250.0/24 to 10.50.0.0/16
00110    38822     2424246 allow ip from 10.50.0.0/16 to 10.205.0.0/16
00110    10972      658944 allow ip from 10.205.0.0/16 to 10.50.0.0/16
00200   531352   199797104 allow ip from 10.16.0.0/16 to 10.26.0.0/16
00300  2253764   742949504 allow ip from 10.50.0.0/16 to 10.16.0.0/16
00400  2655539  1297393740 allow ip from 10.16.0.0/16 to 10.50.0.0/16
00500   222852   198696902 allow ip from 10.58.0.0/16 to 10.16.0.0/16
00600   198040    93069028 allow ip from 10.16.0.0/16 to 10.58.0.0/16
00700  1108462   658486268 allow ip from 10.72.0.0/16 to 10.16.0.0/16
00800  1130958   677203022 allow ip from 10.16.0.0/16 to 10.72.0.0/16
00900   304608   272951682 allow ip from 10.77.0.0/16 to 10.16.0.0/16
01000   249172   108385266 allow ip from 10.16.0.0/16 to 10.77.0.0/16
05000 49424087 31152085218 divert 8668 ip from any to any via em1
05100 69600467 40742448809 allow ip from any to any via em0
05200    58583     3896487 allow icmp from any to any
05300    74828     5111996 allow udp from any to any dst-port 53
05400    74466     9836297 allow udp from any 53 to any
05500 28120301 27503205026 allow ip from any to 192.168.2.2
05600 23757387  4072072900 allow ip from 192.168.2.2 to any
05700        0           0 allow ip from 10.50.0.154 to any
05800        0           0 allow ip from any to 10.50.0.154
05900        0           0 allow ip from 10.50.0.152 to any
06000        0           0 allow ip from any to 10.50.0.152
06100        0           0 allow ip from 10.50.0.162 to any
06200        0           0 allow ip from any to 10.50.0.162
06300        0           0 allow ip from 10.50.0.2 to any
06400        0           0 allow ip from any to 10.50.0.2
06500   787206    84586892 allow ip from any to me
06600        0           0 allow ip from me to any
65535       79        9443 allow ip from any to any

Route : Linux
route add -net 10.50.0.0 netmask 255.255.0.0 gw 10.50.4.201

Route : FreeBSD
route add 10.205.250.0/24 10.50.4.210

Может есть какие нибуть ньансы что надо сделать , подсобите плиз.