VPN - a large number of TCP errors and then no connection?

Question

VPN

I installed pptpd on a VPS with Debian Lenny and I'm testing access to it with different devices.
Installed like this (based on several how-to):

# apt-get install pptpd<br/>
# vi /etc/pptpd.conf<br/>
localip 10.60.60.1 <br/>
remoteip 10.60.60.50-150<br/>
# vi /etc/ppp/pptpd-options - добавил<br/>
ms-dns [DNS1 IP]<br/>
ms-dns [DNS2 IP]<br/>
mtu 1000 &lt;- исправило соединение с iPad. <br/>
mru 1200 &lt;-<br/>
# vi /etc/ppp/chap-secrets<br/>
myusername pptpd mypasswd *<br/>
# mknod /dev/ppp c 108 0 &lt;- ликвидировало ошибку 619 с закрытием соединения.<br/>
# /etc/init.d/pptpd restart<br/>
# vi /etc/sysctl.conf<br/>
net.ipv4.ip_forward=1<br/>
# sysctl net.ipv4.ip_forward=1<br/>
# iptables -t nat -A POSTROUTING -s 10.60.60.0/24 -o eth0 -j MASQUERADE<br/>

Created a pptp connection in Windows XP - within half an hour everything works fine. Additional tests showed that this was lucky - if you open maps.google.com in the browser, it stops delivering packets almost immediately (many requests?).
Android (HTC Desire) - connects, works for several minutes, then starts flooding /var/log/messages on the server with messages like "Protocol-Reject for unsupported protocol ..." Doesn't disconnect, but doesn't browse either.
iPAD - connects, pings google.com in zTools, but Safari and other programs do not see the Internet. Fixed by adding mtu 1000 and mru 1200 to /etc/ppp/pptpd-options. It began to work normally.
Tried tcpdump after connection was established:

# tcpdump -A -s0 -n -i ppp0 host 10.60.60.50 -w dump.txt<br/>

and see what's going on in Wireshark. Shows a large block of normal packets, and then a lot of [TCP Dup ACK] and [TCP Retransmission] errors. Up to 10 pieces in a row.
Run Wireshark on the Windows client and open map.google.com, run tcpdump on the server. Several packets passed, because a bunch of garbage Dup ACK, Retramsmission, then solid SYNs on the client from different ports:
10.60.60.50 74.125.87.99 TCP ecnp > http [SYN] Seq=0 Win=16384 Len=0 MSS=1160
And on the server
tcpdump -A -s0 -n -i ppp0 host 10.60.60.50
writes 0 packets.
If you have any ideas, tell me how to deal with this whole thing or where else to ask.
Thank you!

Answer 1

iPad'u must be told to let all traffic through vpn'y, the default VPN in iOS is used, who would have thought, to a private network. cl.ly/2T0o1d0m1d3w1P1Y2F2O Even if it doesn't climb with the checkbox checked, the gateway default is not transmitted.

Answer 2

For Android: code.google.com/p/android/issues/detail?id=4706
This is a bug and hasn't been fixed yet. Unless in the 4th version.
Use L2TP/IPSec.