LinkChecker checks websites and HTML documents for broken links.
Features are:

* recursive checking

* multithreaded

* output in colored or normal text, HTML, SQL, CSV, XML or a sitemap
graph in different formats

* HTTP/1.1, HTTPS, FTP, mailto:, news:, nntp:, Gopher, Telnet and
local file links support

* restriction of link checking with regular expression filters for
URLs

* proxy support

* username/password authorization for HTTP and FTP

* robots.txt exclusion protocol support

* i18n support

* a command line interface

* a (Fast)CGI web interface (requires HTTP server)