www 子域工作，未知原因

我有一個在 Apache2 上執行的域（來自 Strato）的虛擬伺服器。我唯一執行的站點具有以下虛擬主機：

<IfModule mod_ssl.c>
<VirtualHost *:443>
   # 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 www.example.com

   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                                                                                                                                         
SSLCertificateFile /etc/letsencrypt/live/example.de/fullchain.pem                                                                                                                   
SSLCertificateKeyFile /etc/letsencrypt/live/example.de/privkey.pem                                                                                                                  
Include /etc/letsencrypt/options-ssl-apache.conf                                                                                                                                           
ServerName www.example.de
</VirtualHost>
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet
</IfModule>

和以下 apache2ctl -S：

AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using xxx:xxx:xxx:xxxx::x. Set the 'ServerName' directive globally to suppress this message
VirtualHost configuration:
*:443                  is a NameVirtualHost
   default server www.example.de (/etc/apache2/sites-enabled/vps.conf:2)
   port 443 namevhost www.example.de (/etc/apache2/sites-enabled/vps.conf:2)
ServerRoot: "/etc/apache2"
Main DocumentRoot: "/var/www/html"
Main ErrorLog: "/var/log/apache2/error.log"
Mutex ssl-stapling: using_defaults
Mutex ssl-cache: using_defaults
Mutex default: dir="/var/lock/apache2" mechanism=fcntl 
Mutex mpm-accept: using_defaults
Mutex watchdog-callback: using_defaults
Mutex rewrite-map: using_defaults
PidFile: "/var/run/apache2/apache2.pid"
Define: DUMP_VHOSTS
Define: DUMP_RUN_CFG
User: name="www-data" id=33
Group: name="www-data" id=33

畢竟我讀過我應該無法訪問 www.example.com 下的伺服器，因為我從未配置我的 DNS 條目以匹配該子域。我只有條目 example.de 並相應地設置了 IP。但它確實想在 www 下訪問我的伺服器，所以我將 ServerName 更改為 www.example.com。有趣的是，我可以在 www.example.com 和 example.com 下訪問我的伺服器，並且沒有證書錯誤。

這是我不明白的事情，但我願意理解，因為它困擾著我。

僅供參考：伺服器正在執行 owncloud。

謝謝！

這裡的關鍵是“預設伺服器”。Apache 總是有一個“預設伺服器”……它將接受主機名與定義的任何內容不匹配的任何站點的連接。

在這種情況下，正如您的日誌正確顯示的那樣：

default server www.example.de (/etc/apache2/sites-enabled/vps.conf:2)

www.example.de 是您的預設站點，任何不匹配的主機名都將發送到該站點。

我通常建議人們為預設站點設置一個標準的“404”站點，以告訴人們他們沒有到達正確的站點……然後確保正確定義了正確的域。

引用自：https://serverfault.com/questions/785055