我正在尝试通过外部 IP 地址连接到新安装的 Apache Web 服务器。通过 127.0.0.1 连接没问题，只是使用外部 IP 地址时出现问题。
我的操作系统是Ubuntu 13.10。我正在使用 Apache 2.4 并监听端口 80。
我已经在路由器上设置了转发，并使用 http://canyouseeme.org/ 上的服务进行了检查，其中端口 80 显示为开放。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/，其中显示我的网站已启动？？？
如果有帮助的话，我也尝试了所有这些与其他端口只是为了测试。
我的 ufw 未激活，但是，我的 iptables 中确实有一行，我添加了这一行作为解决问题的一部分，内容如下：
26 1557 ACCEPT tcp -- any any anywhere anywhere tcp dpt:http
如果有帮助的话，我已经在下面包含了我的 Apache 配置文件。
# 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.conf
# 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
如果有人可以通过为我指明正确的方向来提供帮助，那真的会有帮助。
（请注意，我现在已经将监听端口更改为8000）
sudo netstat -napW | grep apache
tcp6 0 0 :::8000 :::* LISTEN 1118/apache2
对于 telnet (telnet xxx.xxx.xxx.xxx 8000)，它现在的行为有所不同，因为它不会再连接。它只是尝试连接然后超时。尽管我的端口 8000 在 canyouseeme.org 上显示为开放状态，但对每个人而言，“Down”也不再表示“已启动”。
我的访问日志仅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，但是有一些条目，并且作为一个新手，我不愿意只是假设，所以我在下面包含了最后几个条目。
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，但我刚刚对我的外部 IP 地址上的端口 8000 进行了 nmap 扫描，并且它显示为已过滤？这是结果：
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 监听，当建立连接时它会提供一个小的 HTML 文件，并且发生同样的情况。 Netcat 通过 127.0.0.1 和 192.168.1.2（我的本地 IP 地址）提供文件服务，而不是通过外部 IP 地址？这是我用过的：
while true; do nc -l 192.168.1.2 -p 8000 -q 1 < test.html; done
我也尝试过：
while true; do nc -l 0.0.0.0 -p 8000 -q 1 < test.html; done
但是没有效果。
***** 耶！正在工作*****
这是多种事物的结合，尽管其中一个我仍然不明白。
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。我之前读过这一点，我尝试通过使用外部服务（downforeveryone 等）来测试来取消它。
我不明白的奇怪的事情（我认为这也更复杂）是由于某种原因我无法在 8000 上转发？如果我这样做，那就行不通了。
目前我仍然有 Apache 监听 8000 端口，我的路由器将请求从 80 端口转发到 8000 端口，一切正常；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。
sudo iptables -I INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT这对我有帮助。防火墙阻止了端口 80。
（最后还需要
sudo service iptables save