我有当前代理模块启用，并正常工作：
$ apache2ctl -M | grep proxy proxy_module (shared) proxy_fcgi_module (shared) 当我启用mod_proxy_http与a2enmod proxy_http和service apache2 restart ，Apache返回错误，如果mod_proxy未启用：
oct 16 10:55:45 apachectl [15243]：apache2：/etc/apache2/apache2.conf中第140行的语法错误：/etc/apache2/mods-enabled/proxy_http.load第2行的语法错误：无法加载/usr/lib/apache2/modules/mod_proxy_http.so放入服务器：/usr/lib/apache2/modules/mod_proxy_http.so：undefined symbol：ap_proxy_check_connection
ap_proxy_check_connection是一个mod_proxy.h方法https://ci.apache.org/projects/httpd/trunk/doxygen/group__MOD__PROXY.html#ga618c0e1bede21bdd3af5d6a802671cae
也许模块顺序加载的一些问题？
谢谢。
更新：在IncludeOptional指令之前添加LoadModule mod_proxy后，问题是相同的。
$ vi /etc/apache2/apache2.conf Include /etc/apache2/mods-available/proxy.load Include /etc/apache2/mods-available/proxy.conf # Include module configuration: IncludeOptional mods-enabled/*.load IncludeOptional mods-enabled/*.conf $ apache2ctl -M | grep proxy [Mon Oct 16 11:14:00.205439 2017] [so:warn] [pid 19944] AH01574: module proxy_module is already loaded, skipping proxy_module (shared) proxy_fcgi_module (shared) $ a2enmod proxy_http Considering dependency proxy for proxy_http: Module proxy already enabled Enabling module proxy_http. To activate the new configuration, you need to run: systemctl restart apache2 $ apache2ctl -M | grep proxy [Mon Oct 16 11:14:11.256292 2017] [so:warn] [pid 20006] AH01574: module proxy_module is already loaded, skipping apache2: Syntax error on line 142 of /etc/apache2/apache2.conf: Syntax error on line 2 of /etc/apache2/mods-enabled/proxy_http.load: Cannot load /usr/lib/apache2/modules/mod_proxy_http.so into server: /usr/lib/apache2/modules/mod_proxy_http.so: undefined symbol: ap_proxy_check_connection