{"id":4,"date":"2005-02-26T12:38:29","date_gmt":"2005-02-26T11:38:29","guid":{"rendered":"http:\/\/blog.blackdown.de\/2005\/03\/08\/exim-4-and-dynamic-ip-addresses\/"},"modified":"2016-10-29T03:51:03","modified_gmt":"2016-10-29T01:51:03","slug":"exim-4-and-dynamic-ip-addresses","status":"publish","type":"post","link":"https:\/\/blackdown.de\/articles\/exim-4-and-dynamic-ip-addresses\/","title":{"rendered":"Exim 4 and Dynamic IP-Addresses"},"content":{"rendered":"<p>I&#8217;ve recently changed my network connection at home to a provider which assigns dynamic addresses. <a href=\"http:\/\/www.exim.org\">Exim<\/a> always provided a broken HELO\/EHLO name to my smarthost since then because my externally visible hostname changes each time I connect. I&#8217;m now using Exim&#8217;s Perl interface to lookup the assigned hostname when connecting my smarthost:<\/p>\n<ul>\n<li><code>\/etc\/exim4\/exim.pl<\/code>:<br \/>\n<em>Don&#8217;t forget to change <code>ppp0<\/code> to the interface you want to handle!<\/em><\/p>\n<pre>\r\n#! \/usr\/bin\/perl\r\n\r\n# Requires libio-interface-perl\r\n\r\nuse strict;\r\nuse IO::Socket;\r\nuse IO::Interface;\r\n\r\nsub get_remote_helo_data()\r\n{\r\n    my $s = IO::Socket::INET-&gt;new(Proto =&gt; 'udp');\r\n    my $addr = inet_aton($s-&gt;if_addr('ppp0'));\r\n    my $hostname = gethostbyaddr($addr, AF_INET);\r\n\r\n    $hostname = '' if (!$hostname);\r\n\r\n    return $hostname;\r\n}\r\n<\/pre>\n<\/li>\n<li><code>\/etc\/exim4\/conf.d\/main\/50_exim4-localconfig_perl<\/code>:\n<pre>\r\n#main\/50_exim4-localconfig_perl\r\nperl_at_start = true\r\nperl_startup = do '\/etc\/exim4\/exim.pl'\r\n<\/pre>\n<\/li>\n<li>Add the following code to the appropriate transport, e.g. <code>remote_smtp_smarthost<\/code>:\n<pre>\r\nhelo_data = \\\r\n  ${if &gt;{${strlen:${perl{get_remote_helo_data}}}}{0} \\\r\n                 {${perl{get_remote_helo_data}}} \\\r\n                 {$primary_hostname}}\r\n<\/pre>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>I&#8217;ve recently changed my network connection at home to a provider which assigns dynamic addresses. Exim always provided a broken HELO\/EHLO name to my smarthost since then because my externally visible hostname changes each time I connect. I&#8217;m now using Exim&#8217;s Perl interface to lookup the assigned hostname when connecting my smarthost: \/etc\/exim4\/exim.pl: Don&#8217;t forget<br \/>[&rarr; <a href=\"https:\/\/blackdown.de\/articles\/exim-4-and-dynamic-ip-addresses\/\" class=\"more-link\">Read the rest of this entry<\/a>]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[6,3,7],"tags":[],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v18.0 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<meta name=\"description\" content=\"I&#039;ve recently changed my network connection at home to a provider which assigns dynamic addresses. 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