Page 1 of 1

[Closed] how to split tunnel with OpenVPN

Posted: Sat May 28, 2011 9:46 am
by ulissex
Hi

I have a problem with my OpenVPN client (on windows XP). Its the same problem discussed here:

http://forums.openvpn.net/topic7869.html

but I found no resolution to it.

I use OpenVPN to connect to VPN server we have at work, but when I'm on VPN I cannot use my home internet connection.

This is my netstat -nr

Image

my default gateway is 192.168.1.1

now I tryed to past this at the end of my config file:

route-nopull
route "ip gateway of my VPN workserver" 255.255.255.0

but nothing

I tryed with

route-nopull
route 192.168.1.1 255.255.255.0 net_gateway
route "ip gateway of my VPN workserver" 255.255.255.0 vpn_gateway

but nothing

Anyone can help me?

Re: how to split tunnel with OpenVPN

Posted: Sat May 28, 2011 9:03 pm
by janjust
so you want to overrule the 'redirect-gateway def1' that is pushed out by the company VPN? normally a company VPN has a pretty good reason for pushing this out...

If you want to access your home LAN resources all you have to add to the client config is

Code: Select all

route 192.168.1.0 255.255.255.0 net_gateway
If you want to stop using 'redirect-gateway' then you have to know all routes that need to go to the company LAN and you need to add them yourself, e.g.

Code: Select all

route-nopull
route a.b.c.d 255.255.255.0 vpn_gateway
route e.f.g.h 255.255.255.0 vpn_gateway
etc.

Re: how to split tunnel with OpenVPN

Posted: Sat May 28, 2011 10:20 pm
by ulissex
Thanks for the reply, but I guess there is something I'm missing (I'm very new to all that). I add the route print after I connect to VPN:

Image

131.114.175.35 is the IP of 1 of the 3 servers used to for VPN service (the other 2 IP ends with 34 and 36), 131.114.241.92 is the IP I have after I connect to VPN.
131.114.241.1 is the gateway after I connect to vpn. 192.168.1.124 and 192.168.56.1 I guess have something to do with the wifi router of my residence, its an open wifi access point.
So a.b.c.d in my case is 131.114.175.35? and I have to add other 2 lines with the other 2 VPN server's IP?

I have seen other kinds of solutions too:

topic7806.html#p11133
and
http://dltj.org/article/openvpn-split-r ... ier_0_1524

but nothing came out. Its possible to use a batch script to split the traffic? Its possible that VPN was structured in such a way that split tunneling is impossible?

Thanks

Re: how to split tunnel with OpenVPN

Posted: Sat May 28, 2011 10:27 pm
by janjust
the

Code: Select all

route-nopull
did not seem to have any effect? set the verbosity to 5 on the client side, reconnect the client and post the log file here.

Re: how to split tunnel with OpenVPN

Posted: Sun May 29, 2011 1:10 am
by ulissex
Hi thanks for the quick reply, this forum is great!!

I set verbosity to 5 and this is the log (I just wiped off some sensitive infos, nothing important)

Sun May 29 03:17:42 2011 us=22398 Current Parameter Settings:
Sun May 29 03:17:42 2011 us=22443 config = 'vpnSBA.ovpn'
Sun May 29 03:17:42 2011 us=22452 mode = 0
Sun May 29 03:17:42 2011 us=22460 show_ciphers = DISABLED
Sun May 29 03:17:42 2011 us=22469 show_digests = DISABLED
Sun May 29 03:17:42 2011 us=22477 NOTE: --mute triggered...
Sun May 29 03:17:42 2011 us=22498 213 variation(s) on previous 5 message(s) suppressed by --mute
Sun May 29 03:17:42 2011 us=22510 OpenVPN 2.1_beta7 Win32-MinGW [SSL] [LZO2] built on Nov 12 2005
Sun May 29 03:17:50 2011 us=970368 LZO compression initialized
Sun May 29 03:17:50 2011 us=970543 Control Channel MTU parms [ L:1576 D:140 EF:40 EB:0 ET:0 EL:0 ]
Sun May 29 03:17:51 2011 us=50703 RESOLVE: NOTE: vpnsba.unipi.it resolves to 3 addresses, choosing one by random
Sun May 29 03:17:51 2011 us=50755 Data Channel MTU parms [ L:1576 D:1450 EF:44 EB:135 ET:32 EL:0 AF:3/1 ]
Sun May 29 03:17:51 2011 us=50838 Local Options String: 'V4,dev-type tap,link-mtu 1576,tun-mtu 1532,proto TCPv4_CLIENT,comp-lzo,cipher BF-CBC,auth SHA1,keysize 128,key-method 2,tls-client'
Sun May 29 03:17:51 2011 us=50867 Expected Remote Options String: 'V4,dev-type tap,link-mtu 1576,tun-mtu 1532,proto TCPv4_SERVER,comp-lzo,cipher BF-CBC,auth SHA1,keysize 128,key-method 2,tls-server'
Sun May 29 03:17:51 2011 us=50914 Local Options hash (VER=V4): '31fdf004'
Sun May 29 03:17:51 2011 us=50944 Expected Remote Options hash (VER=V4): '3e6d1056'
Sun May 29 03:17:51 2011 us=51012 Attempting to establish TCP connection with 131.114.175.34:1194
Sun May 29 03:17:51 2011 us=97081 TCP connection established with 131.114.175.34:1194
Sun May 29 03:17:51 2011 us=97138 Socket Buffers: R=[8192->8192] S=[8192->8192]
Sun May 29 03:17:51 2011 us=97168 TCPv4_CLIENT link local: [undef]
Sun May 29 03:17:51 2011 us=97198 TCPv4_CLIENT link remote: 131.114.175.34:1194
[...]
Sun May 29 03:17:53 2011 us=747145 Data Channel Encrypt: Cipher 'BF-CBC' initialized with 128 bit key
Sun May 29 03:17:53 2011 us=747187 NOTE: --mute triggered...
Sun May 29 03:17:53 2011 us=747552 4 variation(s) on previous 5 message(s) suppressed by --mute
Sun May 29 03:17:53 2011 us=747590 [server] Peer Connection Initiated with 131.114.175.34:1194
Sun May 29 03:17:54 2011 us=757297 SENT CONTROL [server]: 'PUSH_REQUEST' (status=1)
Sun May 29 03:17:54 2011 us=952671 PUSH: Received control message: 'PUSH_REPLY,redirect-gateway,dhcp-option DNS 131.114.241.1,route-gateway 131.114.241.1,ping 10,ping-restart 120,ifconfig 131.114.241.20 255.255.255.0'
Sun May 29 03:17:54 2011 us=952729 Options error: option 'redirect-gateway' cannot be used in this context
Sun May 29 03:17:54 2011 us=952823 OPTIONS IMPORT: timers and/or timeouts modified
Sun May 29 03:17:54 2011 us=952848 OPTIONS IMPORT: --ifconfig/up options modified
Sun May 29 03:17:54 2011 us=952864 OPTIONS IMPORT: route-related options modified
Sun May 29 03:17:54 2011 us=952880 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Sun May 29 03:17:54 2011 us=975561 TAP-WIN32 device [Connessione alla rete locale (LAN) 3] opened: \\.\Global\{0AE75FC7-2C40-4D4D-BEFA-FB93818AD92E}.tap
Sun May 29 03:17:54 2011 us=976474 TAP-Win32 Driver Version 8.3
Sun May 29 03:17:54 2011 us=976508 TAP-Win32 MTU=1500
Sun May 29 03:17:54 2011 us=980258 Notified TAP-Win32 driver to set a DHCP IP/netmask of 131.114.241.20/255.255.255.0 on interface {0AE75FC7-2C40-4D4D-BEFA-FB93818AD92E} [DHCP-serv: 131.114.241.0, lease-time: 31536000]
Sun May 29 03:17:54 2011 us=980293 DHCP option string: 06048372 f101
Sun May 29 03:17:54 2011 us=981522 Successful ARP Flush on interface [4] {0AE75FC7-2C40-4D4D-BEFA-FB93818AD92E}
Sun May 29 03:17:54 2011 us=995837 TEST ROUTES: 0/0 succeeded len=2 ret=0 a=0 u/d=down
Sun May 29 03:17:54 2011 us=996173 Route: Waiting for TUN/TAP interface to come up...
Sun May 29 03:17:56 2011 us=8048 TEST ROUTES: 0/0 succeeded len=2 ret=0 a=0 u/d=down
Sun May 29 03:17:56 2011 us=8149 Route: Waiting for TUN/TAP interface to come up...
Sun May 29 03:17:56 2011 us=792054 TEST ROUTES: 2/2 succeeded len=2 ret=1 a=0 u/d=up
Sun May 29 03:17:56 2011 us=792100 route ADD 131.114.0.0 MASK 255.255.255.255 131.114.241.1
Sun May 29 03:17:56 2011 us=802690 Route addition via IPAPI succeeded
Sun May 29 03:17:56 2011 us=802733 route ADD 198.81.200.2 MASK 255.255.255.255 131.114.241.1
Sun May 29 03:17:56 2011 us=834698 Route addition via IPAPI succeeded
Sun May 29 03:17:56 2011 us=834740 Initialization Sequence Completed


Btw I guess I'm barely finding some light in this dark tunnel :)

I was able to di split tunneling for part of the VPN sites adding

route-nopull
route 131.114.0.0 255.255.255.255 vpn_gateway
route 198.81.200.2 255.255.255.255 vpn_gateway

198.81.200.2 is the IP of one of the VPN sites and I can navigate on internet and watch it (its a journal)

but when I try to add more journals, I dunno why, they aren't recognized and so I can't get in the them.

Re: how to split tunnel with OpenVPN

Posted: Sun May 29, 2011 1:44 am
by Bebop
ulissex wrote: route 131.114.0.0 255.255.255.255 vpn_gateway
After some help via PM, I said I would join you in the main thread here with Janjust, so here I am :]

Just one thing to point out. Is 131.114.0.0 a subnet or a real IP?

If its a real IP then fine, what you did it right... but.. if it is a subnet, you need to use not 255.255.255.255, but instead, 255.255.0.0

Maybe useful, maybe not. Depends if 131.114.0.0 is subnet or single IP.

Re: how to split tunnel with OpenVPN

Posted: Sun May 29, 2011 2:50 pm
by ulissex
hi

I think I finally found a solution, simply adding:

Code: Select all

route-nopull
route "IP I want to see through the VPN 1" 255.255.255.255 vpn_gateway
route "IP I want to see through the VPN 2" 255.255.255.255 vpn_gateway
etc...

I had to find manually all the IP of the journals I need and I added. If I want to add the whole subnet of the journal site, my mask will become 255.255.255.0 and so on. I need to make some more tries, but now I have both internet and VPN on.

Really a big thanks to janjust an Bebop, I really appreciated your help