目錄
- 前言
- Apache快速上手
- 修改端口號
- 設置訪問限制
- 配置文件參數詳解
- 限制連接量
- 封禁ip
- 設置賬號密碼訪問
- 參考
前言
前段時間因為某些原因，幾大主流網盤都無法使用，正好手頭上有臺閑置的云服務器，于是就想來搭建一個文件下載服務，用戶只需通過一個鏈接就能下載軟件。
Apache快速上手
經過調研，發現Ubuntu采用Apache2這個軟件就可以快速滿足我的需求。
安裝Apache2
apt-get install apache2
安裝好之后，啟動Apache2服務：
/etc/init.d/apache2 start
查看啟動狀態：
/etc/init.d/apache2 status
然后，訪問服務器的公網ip或域名，就可以看到如下界面，此時說明Apache正常工作：
最后在/var/www/html路徑下，刪除index.html，上傳自己想要被下載的文件，再次訪問，就可以進行下載了。
(注：如果是云服務器，還需要在安全組開放80和443端口號)
同時，也可以通過域名/文件名的方式直接給別人一個鏈接，進行下載。
如果有一臺單獨的服務器用于臨時文件的分享，這樣很快就搞定了。
下面來繼續進行深入研究，考慮更現實的場景。
修改端口號
Apache2默認采用的是80端口號，因此直接通過公網ip或域名就能訪問?，F實中，很多服務器本身就部署了許多其它服務，80端口號往往被占用，因此就需要將Apache2改成其它訪問端口。
修改端口，首先需要修改/etc/apache2/ports.conf這個文件：
這里吧80改成其它不沖突的端口號，我這里以1024為例
#Listen 80
Listen 1024
<IfModule ssl_module>
Listen 443
</IfModule>
<IfModule mod_gnutls.c>
Listen 443
</IfModule>
然后修改/etc/apache2/sites-available/000-default.conf
#<VirtualHost *:80>
<VirtualHost *:1024>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
注：這個文件中還有一個DocumentRoot，修改該參數可以調整文件系統的根路徑。
修改完成之后，重啟apache2：
/etc/init.d/apache2 restart
此時，就可以通過訪問域名:1024的形式訪問到同樣內容，例如我的服務器訪問url為http://xdxsb.top:1024
設置訪問限制
個人服務器很容易遭到別人的攻擊，如果有人開好多線程來反復請求下載，這就將導致流量帶寬消耗巨大，甚至會讓服務器宕機。因此，長期提供下載服務的服務器必須設置訪問限制。
配置文件參數詳解
訪問限制主要涉及到/etc/apache2/apache2.conf這個配置文件，首先來對該文件進行解讀。
這個文件內容如下：
# 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
#
#
# 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
#
# The directory where shm and other runtime files will be stored.
#
DefaultRuntimeDir ${APACHE_RUN_DIR}
#
# 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 severity 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
參數解釋：
-
PidFile:記錄服務器啟動進程號的文件
-
Timeout:接收和發送前超時秒數
-
KeepAlive:是否允許穩固的連接(每個連接有多個請求)，設為"Off"則停用
-
MaxKeepAliveRequests:在穩固連接期間允許的最大請求數，設為0表示無限制接入
-
KeepAliveTimeout:在同一個連接上從同一臺客戶上接收請求的秒數
-
User/Group:運行的用戶和組
-
HostnameLookups：指定記錄用戶端的名字還是IP地址
例如，本指令為on時記錄主機名，如www.apache.org；為off時記錄IP地址，204.62.129.132。默認值為off，這要比設為on好得多，因為如果設為on則每個用戶端請求都將會至少造成對 nameserver 進行一次查詢。 -
ErrorLog:錯誤日志文件定位
-
LogLevel:控制記錄在錯誤日志文件中的日志信息
可選值：debug，info，notice，warn，error，crit，alert，emerg -
Directory：在標簽對里面可以設置各文件夾屬性
-
Options：控制在特定目錄中將使用哪些服務器特性
- All：除MultiViews之外的所有特性，這是默認設置
- ExecCG：允許使用mod_cgi執行CGI腳本
- FollowSymLinks：服務器允許在此目錄中使用符號連接，如果此配置位于配置段中，則會被忽略
- Includes：允許使用mod_include提供的服務器端包含
- IncludesNOEXEC：允許服務器端包含，但禁用"#exec cmd"和"#exec cgi"，但仍可以從ScriptAlias目錄使用"#include virtual"虛擬CGI腳本
- Indexes：如果一個映射到目錄的URL被請求，而此目錄中又沒有DirectoryIndex(例如：index.html)，那么服務器會返回由mod_autoindex生成的一個格式化后的目錄列表
- MultiViews：允許使用mod_negotiation提供內容協商的"多重視圖"(MultiViews)
- SymLinksIfOwnerMatch：服務器僅在符號連接與其目的目錄或文件的擁有者具有相同的uid時才使用它。 如果此配置出現在配置段中，則將被忽略
-
AllowOverride：確定允許存在于.htaccess文件中的指令類型
語法：AllowOverride All|None|directive-type [directive-type]
如果此指令被設置為None ，那么.htaccess文件將被完全忽略。
directive-type可以是下列各組指令之一：- AuthConfig : 允許使用與認證授權相關的指令
- FileInfo : 允許使用控制文檔類型的指令、控制文檔元數據的指令、mod_rewrite中的指令、mod_actions中的Action指令
- Indexes : 允許使用控制目錄索引的指令
- Limit : 允許使用控制主機訪問的指令
-
Order：控制默認的訪問狀態與Allow和Deny指令生效的順序
- Deny,Allow : Deny指令在Allow指令之前被評估。默認允許所有訪問。任何不匹配Deny指令或者匹配Allow指令的客戶都被允許訪問
- Allow,Deny : Allow指令在Deny指令之前被評估。默認拒絕所有訪問。任何不匹配Allow指令或者匹配Deny指令的客戶都將被禁止訪問
- Mutual-failure : 只有出現在Allow列表并且不出現在Deny列表中的主機才被允許訪問。這種順序與"Order Allow,Deny"具有同樣效果
-
Allow：控制哪些主機可以訪問服務器的該區域?？梢愿鶕鳈C名、IP地址、 IP地址范圍或其他環境變量中捕獲的客戶端請求特性進行控制。
語法：Allow from all|host|env=env-variable [host|env=env-variable] -
Deny：控制哪些主機被禁止訪問服務器的該區域?？梢愿鶕鳈C名、IP地址、 IP地址范圍或其他環境變量中捕獲的客戶端請求特性進行控制。
語法：Deny from all|host|env=env-variable [host|env=env-variable] -
Require：訪問限制
– all granted：表示允許所有主機訪問
– all denied：表示拒絕所有主機訪問
– local：表示僅允許本地主機訪問
– [not] host <主機名或域名列表>：表示允許或拒絕指定主機或域名訪問
– [not] ip <IP地址或網段列表>：表示允許或拒絕指定的IP地址或網段訪問
-
-
AccessFileName：設置分布式配置文件的名字，默認為.htaccess
如果為某個目錄啟用了分布式配置文件功能，那么在向客戶端返回其中的文檔時，服務器將在這個文檔所在的各級目錄中查找此配置文件 -
<FilesMatch"^.ht">：拒絕對.ht開頭文件的訪問,以保護.htaccess文件
-
LogFormat：定義訪問日志的格式
限制連接量
通過上面對配置文件參數的研究，注意到MaxKeepAliveRequests這個參數限制了對于單個連接最大的訪問量為100，因此無需擔心單線程腳本反復頻繁請求的問題。
那么對于高并發的請求，Apache是否有默認設置的策略呢？也是有的，從2.0開始，apache引入了MPM（Multi-Processing Module，多進程處理模塊），MPM有prefork, worker和event這三種模式[4]，可以通過下面的命令查看當前apache所采用的模式：
apachectl -V | grep -i mpm
默認采用的應該是event模式。
這個模式的配置文件位于/etc/apache2/mods-availablempm_event.conf
默認參數：
<IfModule mpm_event_module>
StartServers 2
MinSpareThreads 25
MaxSpareThreads 75
ThreadLimit 64
ThreadsPerChild 25
MaxRequestWorkers 150
MaxConnectionsPerChild 0
</IfModule>
參數解釋：
- StartServers：啟動時進程數
- MinSpareThreads：最小空閑線程數
- MaxSpareThreads：最大空閑線程數
- ThreadLimit：每個進程可以啟動的線程數量上限值
- ThreadsPerChild：每個進程可以啟動的線程數量
- MaxRequestWorkers：線程數量最大值
- MaxConnectionsPerChild：最大連接數限制
我這里沒去調整，先用JMeter來進行一個多線程并發測試：
JMeter下載地址：https://jmeter.apache.org/download_jmeter.cgi
解壓之后，運行apache-jmeter-5.5/bin/jmeter.bat，即可啟動。
創建一個線程組，我這設置了1000個線程數，時間設為0.01秒
再設置HTTP請求，填寫請求域名，端口號，文件路徑
測試結果顯示，請求失敗率為16%，因此我這小破服務器，基本上1000個并發請求都難以滿足。
封禁ip
如果面對惡意攻擊，那最快解決問題的辦法無疑是封禁它的ip，這里嘗試一下封禁本機ip，看看是否有效。
首先查詢本機ip，直接在百度搜索ip，即可查詢到公網ip，注意這里一定要是公網ip，通過ipconfig查詢出的是內網ip。
修改配置文件：
vim /etc/apache2/apache2.conf
修改/var/www/文件內容：
<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride None
<RequireAll>
Require all granted
Require not ip 111.11.81.152
</RequireAll>
</Directory>
重啟服務：
/etc/init.d/apache2 restart
再次訪問，發現權限受限，說明設置成功。
拓展：如果只允許某個固定ip訪問，那么可以這樣修改：
<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride None
# Require all granted
Require ip 111.11.82.8
</Directory>
設置賬號密碼訪問
對于某些私密文件，可以進一步配置賬號密碼進行身份驗證。
首先創建一個文件夾用來保存用戶信息：
mkdir -p /usr/local/conf
然后創建用戶：
htpasswd -c /usr/local/conf/.usr zstar
zstar是我創建的用戶名
輸入密碼后，Apache會以密文方式存儲密碼，可以通過下面的方式查看用戶名和密碼密文：
cat /usr/local/conf/.usr
再次修改配置文件：
vim /etc/apache2/apache2.conf
修改內容：
<Directory /var/www/>
Options Indexes FollowSymLinks
AllowOverride All
AuthName "apache"
AuthType Basic
AuthUserFile "/usr/local/conf/.usr"
Require user zstar
</Directory>
重啟服務：
/etc/init.d/apache2 restart
再次訪問，成功彈出登錄驗證，說明配置成功。
參考
[1]ubuntu搭建http服務器用于下載ubuntu文件：https://blog.csdn.net/yy1695990107/article/details/116976994
[2]Apache2 httpd.conf 配置詳解：https://blog.csdn.net/assassinice/article/details/78854139
[3]Apache的訪問控制：https://blog.csdn.net/m0_54434140/article/details/122249712
[4]apache2三種模式及參數調優：https://blog.csdn.net/zhihui1017/article/details/54959194
