PPTP on DD-WRT can't ping the gateway

[pahud]

I am running IPv4 VPN(PPTP) as client on DD-WRT, the connection is good but I just can't ping the P-t-P endpoint(172.31.255.1) and no traffic can go through the VPN.

Is this a known issue?

Environment: IPv4 VPN (PPTP) (BETA) with DD-WRT  v24-sp2 build 13064
Server: tserv3.fmt2.ipv6.he.net
--
ppp0      Link encap:Point-to-Point Protocol 
          inet addr:184.104.12.182  P-t-P:172.31.255.1  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1450  Metric:1
          RX packets:6 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:98 (98.0 B)  TX bytes:107 (107.0 B)

[jimb]

Have you tried specifying the interface with -I?  Maybe it needs it for P-t-P if it doesn't have that server in the routing table.  Is the default route being set?

Also, by "traffic is not passing", do you mean any IPv4 traffic in general through the PPTP?  Or 6in4 traffic to the tunnel server.  On linux, the latter case requires policy routing set up because the PPTP server and 6in4 server have the same IPv4, so you need to set a policy route such that traffic originating from the PPTP assigned IPv4 takes a route through the PPP interface instead of out of the ethernet NIC directly, which it will do if there is no policy route.

[pahud]

Hi,

I am only trying to route IPv4 traffic through ppp0.  In Mac OS X I can ping the P-t-P IP but in DD-WRT I can't.

macbook:~ macbook$ ifconfig ppp0
ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1448
   inet 184.104.12.182 --> 172.31.255.1 netmask 0xffff0000
macbook:~ macbook$ ping 172.31.255.1
PING 172.31.255.1 (172.31.255.1): 56 data bytes
64 bytes from 172.31.255.1: icmp_seq=0 ttl=64 time=160.242 ms
64 bytes from 172.31.255.1: icmp_seq=1 ttl=64 time=159.673 ms
64 bytes from 172.31.255.1: icmp_seq=2 ttl=64 time=161.747 ms




root@DD-WRT:~# netstat -nr
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
172.31.255.1    0.0.0.0         255.255.255.255 UH        0 0          0 ppp0
10.0.1.0        0.0.0.0         255.255.255.0   U         0 0          0 br0
192.168.1.0     0.0.0.0         255.255.255.0   U         0 0          0 vlan1
184.104.12.0    0.0.0.0         255.255.255.0   U         0 0          0 ppp0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 br0
127.0.0.0       0.0.0.0         255.0.0.0       U         0 0          0 lo
0.0.0.0         192.168.1.254   0.0.0.0         UG        0 0          0 vlan1
root@DD-WRT:~# ping 172.31.255.1
PING 172.31.255.1 (172.31.255.1): 56 data bytes

--- 172.31.255.1 ping statistics ---
10 packets transmitted, 0 packets received, 100% packet loss



root@DD-WRT:~# ifconfig ppp0
ppp0      Link encap:Point-to-Point Protocol 
          inet addr:184.104.12.182  P-t-P:172.31.255.1  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1450  Metric:1
          RX packets:53 errors:0 dropped:0 overruns:0 frame:0
          TX packets:34 errors:10 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3
          RX bytes:3517 (3.4 KiB)  TX bytes:1073 (1.0 KiB)

root@DD-WRT:~# ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: seq=0 ttl=50 time=108.445 ms
64 bytes from 8.8.8.8: seq=1 ttl=50 time=178.911 ms

The default route is set and working. But as I can't ping PPTP P-t-P IP, I just can't route IPv4 traffic through it.

[jimb]

Are you trying to run both PPTP tunnels from the mac and the DD-Wrt simultaneously from behind a NAT?  If so, that could be the problem.  Or perhaps using the same tunnel/pptp entry at the same time?

[pahud]

No I didn't use them at the same time.

[skriglitz]

I'm having the same problem. If i use the default ppp options in the options.vpn script i can't ping 172.31.255.1 but if i change it to

Code Select Expand

nodefaultroute lock noauth debug kdebug 1 nodetach  usepeerdns idle 0 nomppe mtu 1450 mru 1450 name *username* password *password*
I can ping 172.31.255.1 but i can't go any further than that.  I'm looking into routes to get it through but no luck. I did notice though that when I connect through my XP system I get though and can ping through HE and all but it adds a second default route something I haven't gotten to work on my dd-wrt without dropping the connection.