http://thern.org Migrating servers to new datacenters or IP addresses is never entirely problem free, usually due to many DNS servers on the internet not obeying TTL's or caching old records for way too long. These old cached DNS records (usually at different ISP's, major mailservers like google, hotmail, yahoo, etc.) cause problems where they'll route mail to your old server's IP even if you update your DNS.  This also results in clients connecting to your old web IP address and not hitting your new server. When migrating static html sites, having two servers online during a migration isn't a real issue, but when you've got database driven websites (forums, blogs, etc.) this will result in updates going to two different sites, causing all sorts of hassles.  The way around this is to set up your old site as a proxy only, and proxy the results to the new IP address. Here's some configs to allow for proxying Web traffic via Apache, DNS traffic via bind9, and Mail traffic via sen Sat, 03 Apr 2010 00:47:02 +0000 en hourly 1 http://wordpress.org/?v=3.0 http://thern.org/system-administration/minimizing-downtime-associated-with-webdnsmail-ip-address-migrations/ http://thern.org/system-administration/minimizing-downtime-associated-with-webdnsmail-ip-address-migrations/#comments Sat, 03 Apr 2010 00:45:34 +0000 Eric Thern http://thern.org/?p=201 http://thern.org/system-administration/minimizing-downtime-associated-with-webdnsmail-ip-address-migrations/feed/ 0 http://thern.org/linux-and-freebsd/vmware-2-0-x-and-centos-5-4-glibc-crashes-and-instabilities-a-workaround-solution/ http://thern.org/linux-and-freebsd/vmware-2-0-x-and-centos-5-4-glibc-crashes-and-instabilities-a-workaround-solution/#comments Fri, 05 Mar 2010 08:38:23 +0000 Eric Thern http://thern.org/?p=191 http://thern.org/linux-and-freebsd/vmware-2-0-x-and-centos-5-4-glibc-crashes-and-instabilities-a-workaround-solution/feed/ 1 http://thern.org/linux-and-freebsd/yum-update-check-script-runs-via-crontab-and-emails-when-new-updates-are-available/ http://thern.org/linux-and-freebsd/yum-update-check-script-runs-via-crontab-and-emails-when-new-updates-are-available/#comments Fri, 19 Feb 2010 05:03:32 +0000 Eric Thern http://thern.org/eric/?p=160 http://thern.org/linux-and-freebsd/yum-update-check-script-runs-via-crontab-and-emails-when-new-updates-are-available/feed/ 0 http://thern.org/linux-and-freebsd/logrotate-tweaks-to-enhance-rsync-backups/ http://thern.org/linux-and-freebsd/logrotate-tweaks-to-enhance-rsync-backups/#comments Sun, 22 Nov 2009 08:19:55 +0000 Eric Thern http://thern.org/eric/?p=109 http://thern.org/linux-and-freebsd/logrotate-tweaks-to-enhance-rsync-backups/feed/ 0 http://thern.org/linux-and-freebsd/openvz-cache-update-script/ http://thern.org/linux-and-freebsd/openvz-cache-update-script/#comments Tue, 17 Nov 2009 04:23:30 +0000 Eric Thern http://thern.org/eric/?p=94 http://thern.org/linux-and-freebsd/openvz-cache-update-script/feed/ 0 http://thern.org/linux-and-freebsd/plesk-9-x-overuse-policy/ http://thern.org/linux-and-freebsd/plesk-9-x-overuse-policy/#comments Thu, 08 Oct 2009 09:25:35 +0000 Eric Thern http://thern.org/eric/?p=82 http://thern.org/linux-and-freebsd/plesk-9-x-overuse-policy/feed/ 0 http://thern.org/linux-and-freebsd/upgrading-mailscanner/ http://thern.org/linux-and-freebsd/upgrading-mailscanner/#comments Wed, 07 Oct 2009 08:38:32 +0000 Eric Thern http://thern.org/eric/?p=75 http://thern.org/linux-and-freebsd/upgrading-mailscanner/feed/ 0 http://thern.org/linux-and-freebsd/dell-1650-server-and-ipmi-support-on-centos-5/ http://thern.org/linux-and-freebsd/dell-1650-server-and-ipmi-support-on-centos-5/#comments Thu, 17 Jan 2008 22:25:54 +0000 Eric Thern http://thern.org/eric/?p=64 http://thern.org/linux-and-freebsd/dell-1650-server-and-ipmi-support-on-centos-5/feed/ 0 http://thern.org/linux-and-freebsd/sendmail-premissions-error-stopping-mail-from-sending-on-centos-5-1/ http://thern.org/linux-and-freebsd/sendmail-premissions-error-stopping-mail-from-sending-on-centos-5-1/#comments Wed, 16 Jan 2008 22:24:11 +0000 Eric Thern http://thern.org/eric/?p=62 http://thern.org/linux-and-freebsd/sendmail-premissions-error-stopping-mail-from-sending-on-centos-5-1/feed/ 0 http://thern.org/system-administration/freebsd/keeping-servers-and-workstations-on-time-using-cron-and-ntpdate/ http://thern.org/system-administration/freebsd/keeping-servers-and-workstations-on-time-using-cron-and-ntpdate/#comments Tue, 02 Oct 2007 22:16:17 +0000 Eric Thern http://thern.org/eric/?p=52 http://thern.org/system-administration/freebsd/keeping-servers-and-workstations-on-time-using-cron-and-ntpdate/feed/ 0