About VPS with pptpd and iPhone, the vpn tunnel do not stable

While I installed pptpd and enable the pptp in the vps control panel, also I used the command "mknod /dev/ppp c 108 0", and the iPhone can successfully dial the vpn tunnel , also the iptables and ufw configure ok, I could see the flow from the vpn client (iPhone) and outside communicate with the google blogspog server, but the blogger application on the iPhone do not work properly. But some websites such as "www.baidu.com" can browsers properly, why? I do not know.

Searched the goolge, And fould some useful information about iOS with the pptpd service, echo "nopcomp" and "noaccomp" to the pptpd option file "/etc/ppp/pptpd-options".

Ah,.... Amazing.

Maybe I should try openvpn with the iPhone,or do a squid proxy server on it.