pptp vpn連接之後，速度比本地網速慢很多，如何解決？
最近找了台linode 日本的vps裝了pptp，配置好之後，正常連通分配ip，但是連接之後速度慢了很多，
未連接之前測試下載另一台vps上的文件，能達到200KB/s（本人4M寬頻），連上vpn之後再下載速度只有30KB/s左右，請教如何解決……
vps: 日本 linode 3.4.2-linode44/CentOS release 6.2 (Final)
ppp:ppp-2.4.5-17.0.rhel6.i686.rpm
pptp:pptpd-1.3.4.tar.gz
options.pptpd:
###############################################################################
# $Id: options.pptpd,v 1.11 2005/12/29 01:21:09 quozl Exp $
#
# Sample Poptop PPP options file /etc/ppp/options.pptpd
# Options used by PPP when a connection arrives from a client.
# This file is pointed to by /etc/pptpd.conf option keyword.
# Changes are effective on the next connection. See "man pppd".
#
# You are expected to change this file to suit your system. As
# packaged, it requires PPP 2.4.2 and the kernel MPPE module.
###############################################################################
# Authentication
# Name of the local system for authentication purposes
# (must match the second field in /etc/ppp/chap-secrets entries)
name pptpd
# Strip the domain prefix from the username before authentication.
# (applies if you use pppd with chapms-strip-domain patch)
#chapms-strip-domain
# Encryption
# (There have been multiple versions of PPP with encryption support,
# choose with of the following sections you will use.)
# BSD licensed ppp-2.4.2 upstream with MPPE only, kernel module ppp_mppe.o
# {{{
require-pap
require-chap
require-mschap
# Require the peer to authenticate itself using MS-CHAPv2 [Microsoft
# Challenge Handshake Authentication Protocol, Version 2] authentication.
require-mschap-v2
# Require MPPE 128-bit encryption
# (note that MPPE requires the use of MSCHAP-V2 during authentication)
#require-mppe-128
# }}}refuse
# OpenSSL licensed ppp-2.4.1 fork with MPPE only, kernel module mppe.o
# {{{
#-chap
#-chapms
# Require the peer to authenticate itself using MS-CHAPv2 [Microsoft
# Challenge Handshake Authentication Protocol, Version 2] authentication.
#+chapms-v2
# Require MPPE encryption
# (note that MPPE requires the use of MSCHAP-V2 during authentication)
#mppe-40
-------------------------------------------------------------------------------------------------
請教，這是什麼原因導致的，如何解決？
《解決方案》
這個沒辦法 。。用了vpn之後，通訊數據要繞道vpn伺服器的。
《解決方案》
感謝回復 2# maochanglu
主要是速度不穩定，有時測速，速度很快，看youtube很流暢，有時候20-30 KB/s、70-90KB/s，不知道是網路問題還是軟體裝的有問題。
《解決方案》
http://code.google.com/p/chnroutes/
用這個，原理是把國內的IP段加到本地路由表中，這樣就不用走VPN的網關而直接出去了
