Opened 3 years ago

Last modified 3 years ago

#18707 new defect

kernel-pptp instable when more than one vpn connection is used

Reported by: hollari@… Owned by: developers
Priority: normal Milestone: Barrier Breaker 14.07
Component: packages Version: Barrier Breaker 14.07
Keywords: Cc:


Hi !

I have some issues when i use more than one pptp vpn connection.
My configuration :

OpenWRT BARRIER BREAKER (14.07, r42625)
TP-Link TL-WDR4300 v1

/etc/config/network (UMTS/HSDPA Internet CONNECTION):

config interface 'wan'

option proto '3g'
option service 'umts_only'
option apn 'APN'
option delegate '0'
option device '/dev/ttyUSB0'

cat /etc/ppp/options.pptp

idle 0
mppe required,no40,no56,stateless
maxfail 0

cat vpn_loop


while ( test $(ifconfig 3g-wan 2>&1 | grep inet | wc -l) -eq 0 ) do sleep 3; done
sleep 10
pppd nodetach debug call PEERNAME


cat /etc/ppp/peers/PEERNAME

plugin "/usr/lib/pppd/2.4.7/"
pptp_server (SERVERADDRESS)
pptp_window 100
mppe required,no40,no56,stateless
name username
remotename connectionname
file /etc/ppp/options.pptp
ipparam vpnconnection

cat ip-up

case "$6" in


route del default
route del default
route add default dev $1


route del -net
route add -net dev $1
route del -net
route add -net dev $1



All required Packages are from the standard BARRIER BREAKER release.

As long as i only have the Internet Connection + 1 VPN everything looks fine.

As soon as i add another VPN Connection (to another server) the VPNs are performing
very poor. When the Internet Connection is weak, it looks like no traffic
goes through the VPN anymore.
I think the Problem was there in RC3 too, but not so extreme.
(RC3 hat an older pptp Kernel Module)

Unlukily i could not find anything in the logfiles, that could
help to find problem.

Is there a way to increase the verbosity level for the pppd or the pptp module to get
more information into the logfiles ?

Attachments (0)

Change History (3)

comment:1 Changed 3 years ago by hollari@…

Hi !

I have found out something new.
The instability is propably caused by the mobile network operator.
(high Round Trip time, when a only very little Data is transmitted)
Maybe far too big buffers on the Network Operator Side ?!?
So i have tried Wondershaper.

But it always helped only for a little time.

As a workaround i am now RESTARTING the wondershaper
always, when the UMTS connection is (re-)established.

It is running a lot better now (even with both VPN connections acitve),
but I will continue to observe it.

comment:2 Changed 3 years ago by anonymous

I have now done some further investigations.
I flashed my TP-Link 4300 new with the barrier breaker Version.
Installed everything I need for the 3g internet connection.
Installed nothing else.

The Connection is stable for a random time.
Sometimes 3 hours, sometimes 3 days.
(the provider interrupts the connection after 24 hours,

but its working again)

After that time, the internet connection suddenly becomes
slower and slower.
Round-Trip time is going up to 10 seconds (!)

When I do a "ifdown wan && ifup wan",
everything is working fine again.

In my last step, I flashed my old router (TP-Link 1043v1),
that was working perfectly with Backfire 10.03.1 to the
Barrier Breaker 14.07, and replaced the 4300 by this one.

It is working perfectly now for 3 days already; so - i guess - either there is a
hardware fault in my 4300 router, or a bad barrier breaker image
for this type of routers (or a general problem with the USB Controller
of this type of routers ?!?).

comment:3 Changed 3 years ago by anonymous

Update : Barrier Breaker is unstable with 3G/UMTS Modem on my TP-Link1043v1 too.

To be 100% sure, I have now flashed the 1043 back to Backfire 10.03.1.
Internet connectivity works perfect again. For 4 days and 22 hours until now.

Does anyone have an Idea, how I can debug this ?
Has anyone seen the same problems ?

(I would really prefer to use my newer TP4300 with Barrier Breaker as my main router;

thats why I have bought it)

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