HTTP WARNING: HTTP\/1.1 403 Forbidden - 5261 bytes in 0.001 second response time <\/code><\/p>\nThis is unexpected, since I can request the same page in a browser, which returns the Apache Welcome page.<\/p>\n
When I run the check manually I get the same result, as expected:<\/p>\n
# \/usr\/lib64\/nagios\/plugins\/check_http -H localhost
\nHTTP WARNING: HTTP\/1.1 403 Forbidden - 5261 bytes in 0.001 second response time |time=0.000907s|;;;0.000000 size 5261B;;;0<\/code><\/p>\nI checked with curl:<\/p>\n
# curl http:\/\/localhost<\/code><\/p>\nThis returns the HTML source of the Apache Welcome page. It looks like it is working, right? But looking at the headers returned by the Apache server also shows 403 Forbidden<\/code>:<\/p>\n# curl -I http:\/\/localhost
\nHTTP\/1.1 403 Forbidden
\n...<\/code><\/p>\nThe Apache Welcome page gives some hints about this behavior:<\/p>\n
Are you the Administrator?<\/strong><\/p>\nYou should add your website content to the directory \/var\/www\/html\/.<\/p>\n
To prevent this page from ever being used, follow the instructions in the file \/etc\/httpd\/conf.d\/welcome.conf.<\/p><\/blockquote>\n
The \/etc\/httpd\/conf.d\/welcome.conf<\/code> file begins with the following comments and directive:<\/p>\n#\r\n# This configuration file enables the default \"Welcome\" page if there\r\n# is no default index page present for the root URL. To disable the\r\n# Welcome page, comment out all the lines below.\r\n#\r\n# NOTE: if this file is removed, it will be restored on upgrades.\r\n#\r\n<LocationMatch \"^\/+$\">\r\n Options -Indexes\r\n ErrorDocument 403 \/.noindex.html\r\n<\/LocationMatch><\/code><\/pre>\nThe Apache config is specifying that if there is no index page for the document root, return the Welcome page as an error document with a 403 HTTP status code.<\/p>\n
Once I added a basic HTML file at \/var\/www\/html\/index.html<\/code>, Nagios returned a success message:<\/p>\nHTTP OK: HTTP\/1.1 200 OK - 549 bytes in 0.001 second response time<\/code><\/p>\n","protected":false},"excerpt":{"rendered":"The Nagios check_http command reports a warning on localhost on a fresh Nagios installation, even though I can request http:\/\/localhost in a browser. The Welcome page displayed by Apache is an error document though, with HTTP status code 403 Forbidden, rather than 200 OK.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[422],"tags":[73,215,348],"class_list":["post-1665","post","type-post","status-publish","format-standard","hentry","category-sysadmin","tag-apache","tag-curl","tag-nagios"],"_links":{"self":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/1665","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/comments?post=1665"}],"version-history":[{"count":4,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/1665\/revisions"}],"predecessor-version":[{"id":1689,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/posts\/1665\/revisions\/1689"}],"wp:attachment":[{"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/media?parent=1665"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/categories?post=1665"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/osric.com\/chris\/accidental-developer\/wp-json\/wp\/v2\/tags?post=1665"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}