[SOLVED] PPTP connection problems

[songzhuang]

Hi,

I have a VPS running centOS. I created a PPTP VPN using the steps here http://freehostinganswers.com/blog/how- ... nd-ubuntu/

Then on the client side (ubuntu), I am able to make a connection, but cannot access anything on the internet.

How would I go about debugging this? I have doing quite a bit of reading and read somewhere that PPTP may require TUN/TAP module on the server. Is this true?

Please let me know what further info you need and how I can get a handle on the situation, such as where are the transfer logs and debug logs stored.

Thanks.

[songzhuang]

Here is the routing table from the client side (ubuntu)

Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 0.0.0.0 0.0.0.0 U 0 0 0 ppp0
10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 ppp0
192.168.0.0 0.0.0.0 255.255.255.0 U 9 0 0 wlan0
192.168.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 ppp0
203.169.204.151 192.168.0.1 255.255.255.255 UGH 0 0 0 wlan0
203.169.204.151 192.168.0.1 255.255.255.255 UGH 0 0 0 wlan0

Here is my ifconfig output also on the client Ubuntu side:
eth0 Link encap:Ethernet HWaddr d8:9d:67:7c:3e:10
UP BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:65536 Metric:1
RX packets:5240 errors:0 dropped:0 overruns:0 frame:0
TX packets:5240 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:357055 (357.0 KB) TX bytes:357055 (357.0 KB)

ppp0 Link encapoint-to-Point Protocol
inet addr:192.168.0.101 P-t-P:192.168.0.1 Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1400 Metric:1
RX packets:7 errors:0 dropped:0 overruns:0 frame:0
TX packets:22 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:3
RX bytes:94 (94.0 B) TX bytes:3884 (3.8 KB)

wlan0 Link encap:Ethernet HWaddr 9c:2a:70:1c:33:f9
inet addr:192.168.1.101 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::9e2a:70ff:fe1c:33f9/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4518 errors:0 dropped:0 overruns:0 frame:0
TX packets:5020 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3285433 (3.2 MB) TX bytes:767790 (767.7 KB)

[aks]

I read the link you posted and it's written for CentOS 5/6 and you've posted in the CentOS 7 forum.
So two things come to mind here:
1) The RPM doesn't work for CentOS 7 (how did you install it and does it actually work?)
2) They talk of making changes to iptables. Try it with the firewalld switched off (systemctl stop firewalld and systemctl status firewalld to confirm), does it work?

[songzhuang]

My system is actually Centos6. I apologize for posting in CentOS7. Should I repost there or can a moderator move it?

The pppd package works. The connection is made and I get confirmation logs on both the sides.

The firewall has rules for forwarding that are required for the PPTP to work, so turning it off will not work. Anyway, here is the iptables file. Anything amiss?

iptables2.png (9.13 KiB) Viewed 2921 times

[songzhuang]

SOLVED:

I am not sure exactly how it got solved. But here is what happened: I asked the VPS admin to turn on TUN/ TAP. They did so, but disabled the PPP. Then I asked them to enable both. When they did so, my PPTP suddenly started working. I almost fell off the chair when google showed up (I live in China where the government blocks such bad influences to protect me)

For those who may be going down this path: most instructions written on the web are for a dedicated server. If you are on a VPS, you have to ask the admins to turn on stuff. Its quite possible they turned on some other things when they realized I was trying to do a VPN.

Anyway, lots of frustration, learned a lot, finally got there - phew.

[aks]

Good, am glad you got it sorted (even of it's not within your control) - please mark the thread as solved so other's won't waste time trying to resolve something that has already been resolved.