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Topic: lose of nat routed vpn connection on kamikaze

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Hi 

I routed 2 vpn connections on my wrt54gl between a local network and two vpn client on internet:
prerouting_wan
target     prot opt in     out     source               destination
DNAT       udp  --  ppp0   *       0.0.0.0/0            0.0.0.0/0           udp dpt:1494 to:192.168.0.152:1494
DNAT       udp  --  ppp0   *       0.0.0.0/0            0.0.0.0/0           udp dpt:1493 to:192.168.0.152:1493

forwarding_wan
target     prot opt in     out     source               destination
ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp dpts:1493:1500


Theses rules are added (append) in my firewall.user. I mean the kamikaze default rules are still in use.

The VPN server listen to on 1493 and 1394 UDP ports for each vpn client on the internet. I first had a problem with the initial forwarding port rules:
initial forwarding_wan
target     prot opt in     out     source               destination
ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp dpts:1493
ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0           udp dpts:1494

The VPN connection was losed every day (not necessary each 24 hours because of the ppp restart of my internet provider).
I noticed that the vpn packets came through the prerouting rules and were stopped on the forwarding rule, because the port number changed (??!!): Actually the new port was 1497 (for the initial 1494 port) ...
So when I used the new rule (forward of 1493 to 1500 UDP ports) to fix the problem.
The only explanation for me to this weird thing (except the fact that vpn changed its listenning ports) comes from the MASQUERADE use: the output packets was tagged for response (with automatic adress translation) so the returned packets bypassed the prerouting rule (because of the dynamic masquerade rule) and were stopped only on forwarding rule (because of the new UDP port...)

Now, again, every day, I lose the vpn connection. On kamikaze side, there are no suspicious logged packets (wrong ports or address) whatever are the rules.
I tried a vpn client and/or server restart, a iptables reload, nothing changed.
The only option is the wrt45gl reboot.

I saw on another post that I could solve it by adding iptables-mod-nat and kmod-ipt-nat package, but it doesn't solve anything.

Maybe there is a interact problem with the use of pppoe, iptables ?

Please notice that I didn't have this problem with the white russian version.

I'll be very pleased if someone could help me :-)



Here is my configuration:

-----------       ----------       -------------
VPN client| <---> | wrt45g | <---> | VPN server |
-----------       ----------       -------------


kamikaze 7.07 - linksys wrt54gl

Linux version 2.4.34 (nbd@ds10) (gcc version 3.4.6 (OpenWrt-2.0)) #3 Sun Sep 30 20:33:21 CEST 2007

config interface wan
        option ifname   "eth0.1"
        option proto    pppoe
        option username "***"
        option password "***"
        option demand
       option mtu       1400
       option maxfail   0
       option idle 10


base-files-brcm-2.4 - 10-9078 -
bridge - 1.0.6-1 -
busybox - 1.4.2-2 -
dnsmasq - 2.39-1 -
dropbear - 0.50-2 -
iptables - 1.3.7-1 -
iptables-mod-nat - 1.3.7-1 -
iptables-mod-ulog - 1.3.7-1 -
iptraf - 3.0.0-1 -
kernel - 2.4.34-brcm-1 -
kmod-brcm-wl - 2.4.34+4.80.53.0-1 -
kmod-diag - 2+2.4.34-brcm-1 -
kmod-ipt-nat - 2.4.34-brcm-1 -
kmod-ipt-nathelper - 2.4.34-brcm-1 -
kmod-ipt-ulog - 2.4.34-brcm-1 -
kmod-ppp - 2.4.34-brcm-1 -
kmod-pppoe - 2.4.34-brcm-1 -
kmod-switch - 2.4.34-brcm-1 -
kmod-wlcompat - 2.4.34+brcm-6 -
libgcc - 3.4.6-10 -
libmysqlclient - 5.0.18-1 -
libncurses - 5.6-1 -
mtd - 5 -
nas - 4.80.53.0-1 -
ntpclient - 2003_194-4 -
nvram - 1 -
ppp - 2.4.3-8 -
ppp-mod-pppoe - 2.4.3-8 -
uclibc - 0.9.28-10 -
ulogd - 1.24-1 -
ulogd-mod-mysql - 1.24-1 -
wireless-tools - 29-1 -
wlc - 4.80.53.0-1 -
zabbix-agent - 1.3.2-1 -
zlib - 1.2.3-4 -


Module                  Size  Used by    Tainted: P
wlcompat               14944   0 (unused)
ipt_ULOG                3760   3
ip_conntrack_tftp       1712   0 (unused)
ip_nat_irc              2336   0 (unused)
ip_conntrack_irc        3128   1
ip_nat_ftp              2960   0 (unused)
ip_conntrack_ftp        4272   1
ipt_NETMAP               624   0 (unused)
ipt_REDIRECT             640   0 (unused)
ipt_MIRROR              1296   0 (unused)
ppp_async               7884   0 (unused)
wl                    630776   0 (unused)
pppoe                   9320   1
pppox                   1196   1 [pppoe]
ppp_generic            22300   3 [ppp_async pppoe pppox]
slhc                    6064   0 [ppp_generic]
switch-robo             4540   0 (unused)
switch-core             4864   0 [switch-robo]
diag                   25520   0 (unused)

(Last edited by zgalki on 15 Feb 2008, 09:58)

Did you have any solutions? I have a similar problem I can't forward ports easily.

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