CentOS5.5做***拨号服务器的过程。

最新推荐文章于 2025-09-10 16:45:28 发布

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原文链接：http://blog.51cto.com/lionnle/526069

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#网络 #操作系统 #运维

本文介绍如何在Linux上搭建PPTP×××服务器，包括安装所需软件、配置服务器参数、设置防火墙规则等步骤，适用于希望远程访问公司内网资源的用户。

Poptop简介

Poptop，官方网站上的定义是The PPTP Server for Linux，就是利用PPTP（Point to Point Tunneling Protocol，点到点隧道协议）通过Internet访问×××（Virtual Private Network，虚拟局域网），它允许远程用户安全、花费低廉地从Internet上的任何地方访问公司内部网络。

依据连接方式划分，×××可以分为Lan to Lan模式和client to Lan模式两种。前者可以将两个彼此独立的局域网连接起来，就像同属于一个局域网内一样，可以利用Open×××来实现。而后者就该用到Poptop了。

PPTP使用了client-server模式来建立×××连接。大多数微软操作系统都内置了PPTP客户端，所以就不需要安装第三方客户端软件，这就比其他×××技术有了便于安装的优势。

在Poptop出现以前，并没有使用PPTP客户端连接Linux主机的方法存在。使用Poptop，Linux主机可以立即在一个PPTP ×××环境下进行工作。

1 PPTP ×××的基本原理

PPTP ×××本质上是虚拟的点对点链路，它先把到达远方内网的数据包打包成PPP帧，然后再对这些PPP帧进行二次封装，以便于能够在其他物理链路上进行传送。 PPTP ×××有控制信道和数据信道之分，控制信道连接到×××报务器的TCP1723端口，起着控制和管理×××隧道的功能，数据信道是传送PPP帧的信道，关于PPTP数据帧的封装过程如图所示：

在打包PPP帧的过程中，将对PPP数据包进行加密，为了取得最大的安全性，我们这里将使用MPPE加密和MSCHAPv2身份验证方法。下面我们来看看具体配置过程。

注：这里的PPTP只是一种协议，PPTP: Point to Point Tunneling Protocol -- 点到点隧道协议。读者不要被他迷惑了。实现×××有多种协议可以选择，本文讲述的是使用PPTP协议来实现×××，即：PPTP ×××.

2 安装和配置PPTP ××× 服务器

我的系统系统配置：

服务器： CentOS 5.5 final

内核版本： 2.6.18-8.e15

客户端： Window XP Professional

由于Linux本身并没有集成PPTP功能，所以需要安装几种程序以让我们的RedHat支持PPTP，根据内核的版本，下载相应的安装包。

一、下载并安装相关软件

1、下载：

wget http://poptop.sourceforge.net/yum/stable/packages/dkms-2.0.17.5-1.noarch.rpm

wget http://poptop.sourceforge.net/yum/stable/packages/kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm

wget http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-2.rhel5.i386.rpm

wget http://poptop.sourceforge.net/yum/stable/rhel5Server/i386/ppp-2.4.4-14.1.rhel5.i386.rpm

2、安装：

[root@POPTOP home]# ls

dkms-2.0.17.5-1.noarch.rpm lost+found pptpd-1.3.4-2.rhel5.i386.rpm

kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm ppp-devel-2.4.4-14.1.rhel5.i386.rpm

[root@POPTOP home]# rpm -ivh dkms-2.0.17.5-1.noarch.rpm

warning: dkms-2.0.17.5-1.noarch.rpm: Header V3 DSA signature: NOKEY, key ID 862acc42

Preparing... ########################################### [100%]

1:dkms ########################################### [100%]

[root@POPTOP home]# rpm -ivh kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm

warning: kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm: Header V3 DSA signature: NOKEY, key ID 862acc42

Preparing... ########################################### [100%]

1:kernel_ppp_mppe ########################################### [100%]

Creating symlink /var/lib/dkms/kernel_ppp_mppe/1.0.2/source ->

/usr/src/kernel_ppp_mppe-1.0.2

DKMS: add Completed.

Kernel preparation unnecessary for this kernel. Skipping...

Running the pre_build script:

Building module:

cleaning build area....

make KERNELRELEASE=2.6.18-194.el5 -C /lib/modules/2.6.18-194.el5/build M=/var/lib/dkms/kernel_ppp_mppe/1.0.2/build.....(bad exit status: 2)

Error! Bad return status for module build on kernel: 2.6.18-194.el5 (i686)

Consult the make.log in the build directory

/var/lib/dkms/kernel_ppp_mppe/1.0.2/build/ for more information.

Error! Could not locate ppp_generic.ko for module kernel_ppp_mppe in the DKMS tree.

You must run a dkms build for kernel 2.6.18-194.el5 (i686) first.

--------------上面的错误好像没有影响------------------------------------------------------------

[root@POPTOP home]#

[root@POPTOP home]# rpm -qa kernel_ppp_mppe

kernel_ppp_mppe-1.0.2-3dkms

PPTP需要PPP支持，虽然系统本身有PPP功能，但它并不一定支持MPPE. 如果不支持则需要更新系统的PPP组件，参数-U就是更新的意思。

[root@POPTOP home]# rpm -Uvh ppp-2.4.4-14.1.rhel5.i386.rpm

warning: ppp-2.4.4-14.1.rhel5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 862acc42

Preparing... ########################################### [100%]

1:ppp ########################################### [100%]

要使用MPPE加密，还需要内核支持，Linux 2.6.14起Linux核心提供完整的PPTP支援《包括自由版本的MPPE》。查看内核版本可以使用命令：uname –r，如果内核版本低于2.6.14则还要下载一个MPPE内核补丁：kernel-mppe-2.4.20-8.i686.rpm

我的系统：

[root@POPTOP ~]# uname -r

2.6.18-194.el5 所以不需要打补丁了。

[root@POPTOP home]# rpm -ivh pptpd-1.3.4-2.rhel5.i386.rpm

warning: pptpd-1.3.4-2.rhel5.i386.rpm: Header V3 DSA signature: NOKEY, key ID 862acc42

Preparing... ########################################### [100%]

1:pptpd ########################################### [100%]

[root@POPTOP home]#

二，修改配置文件

这里需要修改如下3个配置文件：带底纹的就是需要我们修改的地方，其他加了红色注释的是说明，确实设置的。

/etc/pptpd.conf
/etc/ppp/options.pptpd
/etc/ppp/chap-secrets

I /etc/pptpd.conf 服务pptpd运行时使用的配置文件

###############################################################################

# $Id: pptpd.conf,v 1.10 2006/09/04 23:30:57 quozl Exp $

# Sample Poptop configuration file /etc/pptpd.conf

# Changes are effective when pptpd is restarted.

###############################################################################

# TAG: ppp

# Path to the pppd program, default '/usr/sbin/pppd' on Linux

ppp /usr/sbin/pppd

# TAG: option

# Specifies the location of the PPP options file.

# By default PPP looks in '/etc/ppp/options'

option /etc/ppp/options.pptpd #指定pptpd用到的选项文件

# TAG: debug

# Turns on (more) debugging to syslog

#debug

# TAG: stimeout

# Specifies timeout (in seconds) on starting ctrl connection

# stimeout 10

# TAG: noipparam

# Suppress the passing of the client's IP address to PPP, which is

# done by default otherwise.

#noipparam

# TAG: logwtmp

# Use wtmp(5) to record client connections and disconnections.

logwtmp

# TAG: bcrelay <if>

# Turns on broadcast relay to clients from interface <if>

# bcrelay eth2 #好像用不到，后面再研究

# TAG: delegate

# Delegates the allocation of client IP addresses to pppd.

# Without this option, which is the default, pptpd manages the list of

# IP addresses for clients and passes the next free address to pppd.

# With this option, pptpd does not pass an address, and so pppd may use

# radius or chap-secrets to allocate an address.

#delegate

# TAG: connections

# Limits the number of client connections that may be accepted.

# If pptpd is allocating IP addresses (e.g. delegate is not

# used) then the number of connections is also limited by the

# remoteip option. The default is 100.

#connections 100

# TAG: localip

# TAG: remoteip

# Specifies the local and remote IP address ranges.

# These options are ignored if delegate option is set.

# Any addresses work as long as the local machine takes care of the

# routing. But if you want to use MS-Windows networking, you should

# use IP addresses out of the LAN address space and use the proxyarp

# option in the pppd options file, or run bcrelay.

# You can specify single IP addresses seperated by commas or you can

# specify ranges, or both. For example:

# 192.168.0.234,192.168.0.245-249,192.168.0.254

# IMPORTANT RESTRICTIONS:

# 1. No spaces are permitted between commas or within addresses.

# 2. If you give more IP addresses than the value of connections,

# it will start at the beginning of the list and go until it

# gets connections IPs. Others will be ignored.

# 3. No shortcuts in ranges! ie. 234-8 does not mean 234 to 238,

# you must type 234-238 if you mean this.

# 4. If you give a single localIP, that's ok - all local IPs will

# be set to the given one. You MUST still give at least one remote

# IP for each simultaneous client.

# (Recommended)

localip 192.168.16.110 #这个地址无所谓的，随便指定一个，不过用你拨号的服务器地址比较清晰

remoteip 58.241.84.47,58.241.84.48,58.241.84.49 #你要分配给客户机的地址池

# or

#localip 192.168.0.234-238,192.168.0.245

#remoteip 192.168.1.234-238,192.168.1.245

II /etc/ppp/options.pptpd

就是上面/etc/pptpd.conf中的option所指定的，它是PPP功能组件pppd将使用的配置文件，由于PPTP ×××的加密和验证都与PPP相关，所以PPTP的加密和验证选项都将在这个配置文件中进行配置。

[root@POPTOP ppp]# vi 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 POPTOP #相当于身份验证时的域，一定要和/etc/ppp/chap-secrets中的内容对应

# 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

# {{{

refuse-pap #拒绝pap身份验证

refuse-chap #拒绝chap身份验证

refuse-mschap #拒绝mschap身份验证

# Require the peer to authenticate itself using MS-CHAPv2 [Microsoft

# Challenge Handshake Authentication Protocol, Version 2] authentication.

require-mschap-v2 #采用mschap-v2（Microsoft Challenge Handshake Authentication Protocol, Version 2）身份验证方式

# Require MPPE 128-bit encryption

# (note that MPPE requires the use of MSCHAP-V2 during authentication)

require-mppe-128 #要求128位MPPE加密

# }}}

# 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 # enable either 40-bit or 128-bit, not both

#mppe-128

#mppe-stateless

# }}}

# Network and Routing

# If pppd is acting as a server for Microsoft Windows clients, this

# option allows pppd to supply one or two DNS (Domain Name Server)

# addresses to the clients. The first instance of this option

# specifies the primary DNS address; the second instance (if given)

# specifies the secondary DNS address.

ms-dns 58.241.84.5 #分给客户机的DNS地址

ms-dns 58.241.84.6

# If pppd is acting as a server for Microsoft Windows or "Samba"

# clients, this option allows pppd to supply one or two WINS (Windows

# Internet Name Services) server addresses to the clients. The first

# instance of this option specifies the primary WINS address; the

# second instance (if given) specifies the secondary WINS address.

#ms-wins 10.0.0.3

#ms-wins 10.0.0.4

# Add an entry to this system's ARP [Address Resolution Protocol]

# table with the IP address of the peer and the Ethernet address of this

# system. This will have the effect of making the peer appear to other

# systems to be on the local ethernet.

# (you do not need this if your PPTP server is responsible for routing

# packets to the clients -- James Cameron)

# proxyarp #启用ARP代理，如果分配给客户端的IP与内网卡同一个子网

# Normally pptpd passes the IP address to pppd, but if pptpd has been

# given the delegate option in pptpd.conf or the --delegate command line

# option, then pppd will use chap-secrets or radius to allocate the

# client IP address. The default local IP address used at the server

# end is often the same as the address of the server. To override this,

# specify the local IP address here.

# (you must not use this unless you have used the delegate option)

#10.8.0.100

# Logging

# Enable connection debugging facilities.

# (see your syslog configuration for where pppd sends to)

#debug

# Print out all the option values which have been set.

# (often requested by mailing list to verify options)

#dump

# Miscellaneous

# Create a UUCP-style lock file for the pseudo-tty to ensure exclusive

# access.

lock

# Disable BSD-Compress compression

nobsdcomp

# Disable Van Jacobson compression

# (needed on some networks with Windows 9x/ME/XP clients, see posting to

# poptop-server on 14th April 2005 by Pawel Pokrywka and followups,

# http://marc.theaimsgroup.com/?t=111343175400006&r=1&w=2 )

novj

novjccomp

# turn off logging to stderr, since this may be redirected to pptpd,

# which may trigger a loopback

nologfd

# put plugins here

# (putting them higher up may cause them to sent messages to the pty)

III /etc/ppp/chap-secrets

客户机帐号和密码信息。

# Secrets for authentication using CHAP

# client server secret IP addresses

"123456" POPTOP "123456" "*"

"qwe" * "qwe123456" *

“qwe”是Client端的×××用户名；

“server”对应的是×××服务器的名字，该名字必须和/etc/ppp/options.pptpd文件中指明的一样，或者设置成“*”号来表示自动识别服务器；

“secret”对应的是登录密码；

“IP addresses”对应的是可以拨入的客户端IP地址，如果不需要做特别限制，可以将其设置为“*”号

三启动pptpd服务

启动pptpd

/sbin/service pptpd start