我已经在 CentOS 5 服务器上运行网站大约 1 年了。一切都很顺利，直到我注意到我的服务器上出现了奇怪的停机问题。我刚刚查看了系统图表，发现系统内存已达到最大值，然后 Apache 服务离线了。
到目前为止我一直遇到这种类型的停机情况，但我真的不知道问题出在哪里。
我有一些日志文件，在其中发现了一些奇怪的东西，但我不知道它是否相关。
当服务器宕机时，我会收到此日志var/log/httpd/ssl_error_log
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
[Thu Oct 31 *** 2013] [warn] RSA server certificate is a CA certificate (BasicConstraints: CA == TRUE !?)
我还注意到，昨天，我var/log/secure已经从我的或服务器以外的其他 IP 记录了一些操作。
Oct 30 *** server1 pure-ftpd: (?@***) [INFO] New connection from ***
Oct 30 *** server1 pure-ftpd: (?@***) [INFO] Anonymous user logged in
Oct 30 *** server1 pure-ftpd: (ftp@***) [ERROR] Can't open that file: Permission denied
Oct 30 *** server1 pure-ftpd: (ftp@***) [ERROR] Can't open that file: Permission denied
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Can't change directory to public: No such file or directory
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Can't change directory to incoming: No such file or directory
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Can't change directory to incoming: No such file or directory
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Can't change directory to _vti_pvt: No such file or directory
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Can't change directory to upload: No such file or directory
Oct 30 *** server1 pure-ftpd: (ftp@***) [INFO] Logout.
这意味着有人入侵了我的系统？
有人能告诉我这可能是什么问题吗？我该如何解决？如果您需要，我可以发布更多日志，只需指定哪些！
发生停机时，错误日志显示以下内容：
[Thu Oct 31 *** 2013] [error] server reached MaxClients setting, consider raising the MaxClients setting
[Thu Oct 31 *** 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Oct 31 *** 2013] [warn] RSA server certificate wildcard CommonName (CN) `*.lxlabs.com' does NOT match server name!?
[Thu Oct 31 *** 2013] [notice] ModSecurity for Apache/2.6.7 (http://www.modsecurity.org/) configured.
[Thu Oct 31 *** 2013] [notice] ModSecurity: APR compiled version="1.2.7"; loaded version="1.3.12"
[Thu Oct 31 *** 2013] [warn] ModSecurity: Loaded APR do not match with compiled!
[Thu Oct 31 *** 2013] [notice] ModSecurity: PCRE compiled version="6.6 "; loaded version="8.02 2010-03-19"
[Thu Oct 31 *** 2013] [warn] ModSecurity: Loaded PCRE do not match with compiled!
[Thu Oct 31 *** 2013] [notice] ModSecurity: LUA compiled version="Lua 5.1"
[Thu Oct 31 *** 2013] [notice] ModSecurity: LIBXML compiled version="2.6.26"
[Thu Oct 31 *** 2013] [notice] Digest: generating secret for digest authentication ...
[Thu Oct 31 *** 2013] [notice] Digest: done
[Thu Oct 31 *** 2013] [warn] RSA server certificate wildcard CommonName (CN) `*.lxlabs.com' does NOT match server name!?
[Thu Oct 31 *** 2013] [notice] Apache/2.2.22 (Unix) DAV/2 PHP/5.2.17 mod_ssl/2.2.22 OpenSSL/0.9.8e-fips-rhel5 configured -- resuming normal operations
[Thu Oct 31 *** 2013] [notice] caught SIGTERM, shutting down
[Thu Oct 31 *** 2013] [notice] suEXEC mechanism enabled (wrapper: /usr/sbin/suexec)
[Thu Oct 31 *** 2013] [warn] RSA server certificate wildcard CommonName (CN) `*.lxlabs.com' does NOT match server name!?
[Thu Oct 31 *** 2013] [notice] ModSecurity for Apache/2.6.7 (http://www.modsecurity.org/) configured.
[Thu Oct 31 *** 2013] [notice] ModSecurity: APR compiled version="1.2.7"; loaded version="1.3.12"
[Thu Oct 31 *** 2013] [warn] ModSecurity: Loaded APR do not match with compiled!
[Thu Oct 31 *** 2013] [notice] ModSecurity: PCRE compiled version="6.6 "; loaded version="8.02 2010-03-19"
[Thu Oct 31 *** 2013] [warn] ModSecurity: Loaded PCRE do not match with compiled!
[Thu Oct 31 *** 2013] [notice] ModSecurity: LUA compiled version="Lua 5.1"
[Thu Oct 31 *** 2013] [notice] ModSecurity: LIBXML compiled version="2.6.26"
[Thu Oct 31 *** 2013] [notice] Digest: generating secret for digest authentication ...
[Thu Oct 31 *** 2013] [notice] Digest: done
[Thu Oct 31 *** 2013] [warn] RSA server certificate wildcard CommonName (CN) `*.lxlabs.com' does NOT match server name!?
[Thu Oct 31 *** 2013] [notice] Apache/2.2.22 (Unix) DAV/2 PHP/5.2.17 mod_ssl/2.2.22 OpenSSL/0.9.8e-fips-rhel5 configured -- resuming normal operations