无法通过外部 IP 地址访问 Apache Web 服务器

Question

我正在尝试通过外部 IP 地址连接到我新安装的 Apache Web 服务器。通过 127.0.0.1 连接没问题，这只是使用外部 IP 地址时的问题。

我的操作系统是 Ubuntu 13.10。我正在使用 Apache 2.4 并监听端口 80。

我已经在我的路由器上设置了转发，并通过使用http://canyouseeme.org/上的服务检查了这一点，其中端口 80 显示为打开。我可以使用我的外部 IP 地址并指定端口 80 通过 telnet 建立连接，并且还检查了http://downforeveryoneorjustme.com/那里说我的网站已启动？？？

如果有帮助，我也尝试了所有这些与其他端口的测试。

我的 ufw 不活跃，但是，我的 iptables 中确实有一行，作为我解决问题的一部分，我添加了一行，内容如下：

  26  1557 ACCEPT     tcp  --  any    any     anywhere             anywhere             tcp dpt:http

如果有帮助，我在下面包含了我的 Apache 配置文件。

apache2.conf：

# This is the main Apache server configuration file.  It contains the
# configuration directives that give the server its instructions.
# See http://httpd.apache.org/docs/2.4/ for detailed information about
# the directives and /usr/share/doc/apache2/README.Debian about Debian specific
# hints.
#
#
# Summary of how the Apache 2 configuration works in Debian:
# The Apache 2 web server configuration in Debian is quite different to
# upstream's suggested way to configure the web server. This is because Debian's
# default Apache2 installation attempts to make adding and removing modules,
# virtual hosts, and extra configuration directives as flexible as possible, in
# order to make automating the changes and administering the server as easy as
# possible.

# It is split into several files forming the configuration hierarchy outlined
# below, all located in the /etc/apache2/ directory:
#
#    /etc/apache2/
#    |-- apache2.conf
#    |    `--  ports.conf
#    |-- mods-enabled
#    |    |-- *.load
#    |    `-- *.conf
#    |-- conf-enabled
#    |    `-- *.conf
#     `-- sites-enabled
#         `-- *.conf
#
#
# * apache2.conf is the main configuration file (this file). It puts the pieces
#   together by including all remaining configuration files when starting up the
#   web server.
#
# * ports.conf is always included from the main configuration file. It is
#   supposed to determine listening ports for incoming connections which can be
#   customized anytime.
#
# * Configuration files in the mods-enabled/, conf-enabled/ and sites-enabled/
#   directories contain particular configuration snippets which manage modules,
#   global configuration fragments, or virtual host configurations,
#   respectively.
#
#   They are activated by symlinking available configuration files from their
#   respective *-available/ counterparts. These should be managed by using our
#   helpers a2enmod/a2dismod, a2ensite/a2dissite and a2enconf/a2disconf. See
#   their respective man pages for detailed information.
#
# * The binary is called apache2. Due to the use of environment variables, in
#   the default configuration, apache2 needs to be started/stopped with
#   /etc/init.d/apache2 or apache2ctl. Calling /usr/bin/apache2 directly will not
#   work with the default configuration.


# Global configuration
ServerName localhost

#
# ServerRoot: The top of the directory tree under which the server's
# configuration, error, and log files are kept.
#
# NOTE!  If you intend to place this on an NFS (or otherwise network)
# mounted filesystem then please read the Mutex documentation (available
# at <URL:http://httpd.apache.org/docs/2.4/mod/core.html#mutex>);
# you will save yourself a lot of trouble.
#
# Do NOT add a slash at the end of the directory path.
#
#ServerRoot "/etc/apache2"

#
# The accept serialization lock file MUST BE STORED ON A LOCAL DISK.
#
Mutex file:${APACHE_LOCK_DIR} default

#
# PidFile: The file in which the server should record its process
# identification number when it starts.
# This needs to be set in /etc/apache2/envvars
#
PidFile ${APACHE_PID_FILE}

#
# Timeout: The number of seconds before receives and sends time out.
#
Timeout 300

#
# KeepAlive: Whether or not to allow persistent connections (more than
# one request per connection). Set to "Off" to deactivate.
#
KeepAlive On

#
# MaxKeepAliveRequests: The maximum number of requests to allow
# during a persistent connection. Set to 0 to allow an unlimited amount.
# We recommend you leave this number high, for maximum performance.
#
MaxKeepAliveRequests 100

#
# KeepAliveTimeout: Number of seconds to wait for the next request from the
# same client on the same connection.
#
KeepAliveTimeout 5


# These need to be set in /etc/apache2/envvars
User ${APACHE_RUN_USER}
Group ${APACHE_RUN_GROUP}

#
# HostnameLookups: Log the names of clients or just their IP addresses
# e.g., www.apache.org (on) or 204.62.129.132 (off).
# The default is off because it'd be overall better for the net if people
# had to knowingly turn this feature on, since enabling it means that
# each client request will result in AT LEAST one lookup request to the
# nameserver.
#
HostnameLookups Off

# ErrorLog: The location of the error log file.
# If you do not specify an ErrorLog directive within a <VirtualHost>
# container, error messages relating to that virtual host will be
# logged here.  If you *do* define an error logfile for a <VirtualHost>
# container, that host's errors will be logged there and not here.
#
ErrorLog ${APACHE_LOG_DIR}/error.log

#
# LogLevel: Control the number of messages logged to the error_log.
# Available values: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the log level for particular modules, e.g.
# "LogLevel info ssl:warn"
#
LogLevel warn

# Include module configuration:
IncludeOptional mods-enabled/*.load
IncludeOptional mods-enabled/*.conf

# Include list of ports to listen on
 Include ports.conf


# Sets the default security model of the Apache2 HTTPD server. It does
# not allow access to the root filesystem outside of /usr/share and /var/www.
# The former is used by web applications packaged in Debian,
# the latter may be used for local directories served by the web server. If
# your system is serving content from a sub-directory in /srv you must allow
# access here, or in any related virtual host.
<Directory />
Options FollowSymLinks
AllowOverride None
Require all denied
</Directory>

<Directory /usr/share>
AllowOverride None
Require all granted
</Directory>

<Directory /var/www>
Options Indexes FollowSymLinks
AllowOverride None
Require all granted
</Directory>

#<Directory /srv/>
#    Options Indexes FollowSymLinks
#    AllowOverride None
#    Require all granted
#</Directory>




# AccessFileName: The name of the file to look for in each directory
# for additional configuration directives.  See also the AllowOverride
# directive.
#
AccessFileName .htaccess

#
# The following lines prevent .htaccess and .htpasswd files from being
# viewed by Web clients.
#
<FilesMatch "^\.ht">
Require all denied
</FilesMatch>


#
# The following directives define some format nicknames for use with
# a CustomLog directive.
#
# These deviate from the Common Log Format definitions in that they use %O
# (the actual bytes sent including headers) instead of %b (the size of the
# requested file), because the latter makes it impossible to detect partial
# requests.
#
# Note that the use of %{X-Forwarded-For}i instead of %h is not recommended.
# Use mod_remoteip instead.
#
LogFormat "%v:%p %h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" vhost_combined
LogFormat "%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %O" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

# Include of directories ignores editors' and dpkg's backup files,
# see README.Debian for details.

# Include generic snippets of statements
IncludeOptional conf-enabled/*.conf

# Include the virtual host configurations:
IncludeOptional sites-enabled/*.conf

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

端口配置文件

# If you just change the port or add more ports here, you will likely also
# have to change the VirtualHost statement in
# /etc/apache2/sites-enabled/000-default

Listen 0.0.0.0:80

<IfModule ssl_module>
Listen 443
</IfModule>

<IfModule mod_gnutls.c>
Listen 443
</IfModule>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

站点启用/000-default.conf

<VirtualHost *:80>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
# redirection URLs. In the context of virtual hosts, the ServerName
# specifies what hostname must appear in the request's Host: header to
# match this virtual host. For the default virtual host (this file) this
# value is not decisive as it is used as a last resort host regardless.
# However, you must set it for any further virtual host explicitly.
ServerName localhost

ServerAdmin webmaster@localhost
DocumentRoot /var/www

# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn

ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined

# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
</VirtualHost>

# vim: syntax=apache ts=4 sw=4 sts=4 sr noet

如果有人可以通过将我指向正确的方向来提供帮助，那真的会有所帮助。

（请注意，我现在已将侦听端口更改为 8000）

sudo netstat -napW | grep apache
tcp6       0      0 :::8000                 :::*                    LISTEN      1118/apache2

关于 telnet (telnet xxx.xxx.xxx.xxx 8000)，它现在的行为有所不同，因为它不再连接。它只是尝试连接，然后超时。尽管我的 8000 端口在 canyouseeme.org 上显示为打开状态，但每个人都已关闭。

我的访问日志只显示本地建立的连接。我认为错误日志也没有显示任何内容，但是有条目，作为新手，我不愿意假设，所以我包含了下面的最后几个条目。

normal operations
[Fri Dec 27 22:20:05.672859 2013] [core:notice] [pid 19548:tid 139673813047168] AH00094: Command line: '/usr/sbin/apache2'
[Fri Dec 27 22:49:55.262428 2013] [mpm_event:notice] [pid 19548:tid 139673813047168] AH00491: caught SIGTERM, shutting down
[Sat Dec 28 09:16:57.693712 2013] [mpm_event:notice] [pid 1118:tid 140053653940096] AH00489: Apache/2.4.6 (Ubuntu) configured -- resuming normal operations
[Sat Dec 28 09:16:57.705967 2013] [core:notice] [pid 1118:tid 140053653940096] AH00094: Command line: '/usr/sbin/apache2'

另外，我不知道这是否相关，但我刚刚在我的外部 IP 地址上对端口 8000 进行了 nmap 扫描，它显示为已过滤？结果如下：

PORT     STATE    SERVICE  VERSION
8000/tcp filtered http-alt

更多信息...

我怀疑这可能不是 Apache 的直接问题！我刚刚尝试在同一个端口上设置 netcat 侦听，当建立连接时它会提供一个小的 HTML 文件，并且正在发生同样的事情。Netcat 通过 127.0.0.1 和 192.168.1.2（我的本地 IP 地址）提供文件，而不是通过外部 IP 地址？这是我使用的：

while true; do nc -l 192.168.1.2 -p 8000 -q 1 < test.html; done

我也试过：

while true; do nc -l 0.0.0.0 -p 8000 -q 1 < test.html; done

但无济于事。

***** 好极了！它正在工作 *****

这是一些事情的组合，尽管其中之一我仍然不明白。

这里的主要问题是我一定是个白痴，因为我不知道如果不使用网络环回，您就无法从 LAN 内部连接到外部 IP 地址。事实证明，我的路由器不支持它。我以前读过这个，我试图通过使用外部服务（downforeveryone 等）来测试来取消它。

我没有得到的奇怪的事情（我认为它也更复杂）是由于某种原因我无法在 8000 上转发？如果我这样做，那么它不起作用。

目前我仍然让 Apache 监听端口 8000，我的路由器将请求从端口 80 转发到端口 8000，这很好；但是，如果我将路由器上的端口更改为 8000，使其从 8000 转发到 8000，则它不起作用。

Answer 1

sudo iptables -I INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT

这对我有帮助。防火墙封锁了80端口。
（最后还需要sudo service iptables save重启系统后保存更改。）