As I’ve been mentioning before, the content is this server ( will be migrated to a new server ( These are dedicated servers from The ks26301 server, which I have been using since April 2009, is their 2008 model. Back in 2009, their services got introduced in the Netherlands, and the first 1000 subscribers got a year free. I was one of the lucky.

Anyhow, this is a server from 2008, and the price hasn’t changed (apart from the taxes, that is). The point is, for the same price they offer much better specs. So, it makes sense to migrate. Also, over the past years I am hosting services for certain people, which makes the configuration I’ve been using since 2011 less optimal. I never enticipated the fact I would be offering hosting services to third parties, so even more reason to migrate my services to a new server.

At this point, I would like to highlight one of the issues that arrises during such a migration, and provide a solution for it. The problem is the way DNS works. When I change my DNS entries, it takes a while to propagate through the internet. The old IP address might be cached at some DNS server and so on. Therefore, during the migration, requests may arrive at both the old and the new server. So, how to make this situation transparant to the user?

First, let’s have a look at Apache. We’re going to use the mod_proxy for this purpose. I had this module already installed on my system, therefore, in my /etc/httpd/conf/httpd.conf I have

LoadModule proxy_module modules/
LoadModule proxy_connect_module modules/
LoadModule proxy_ftp_module modules/
LoadModule proxy_http_module modules/
LoadModule proxy_scgi_module modules/
LoadModule proxy_ajp_module modules/
LoadModule proxy_balancer_module modules/

I might check later on a different (non-production) server which of these are actually required for this purpose.

Anyhow, in my /etc/httpd/conf/extra/httpd-vhosts.conf, I use the following to proxy the connection to the new server. Please note my old server resolved the domain.tld to the new server. Just to be sure it won’t get caught up in a loop, I might add it to /etc/hosts as well. (I’ve kept the DocumentRoot in there, but it has no real purpose anymore. Merely a fallback in case the mod_proxy isn’t loaded)

<VirtualHost *:80>
  ServerAdmin webmaster@domain.tld
  DocumentRoot "/path/to/documentroot"
  ServerName domain.tld
  ServerAlias www.domain.tld
  ErrorLog "/var/log/httpd/domain.tld-error_log"
  CustomLog "/var/log/httpd/domain.tld-access_log" combined

  <IfModule mod_proxy.c>
    <Proxy *>
      Order deny,allow
      Allow from all
    ProxyRequests off
    ProxyPassInterpolateEnv On
    ProxyPass / http://www.domain.tld/ interpolate


Next issue, is incoming mail. For now, I start at migrating the websites, and later I will migrate the mail. But as a proof-of-conecpt, I have tested this for one domain which only has a catch-all-forward.

The ks26301 runs exim as smtp server, well, basically, we’re going to tell it to forward mail for the specific domain to the ks3291437 server.

Just below begin routers in the /etc/mail/exim.conf file, we add

  driver = manualroute
  domains = "domain.tld"
  transport = remote_smtp
  route_list = *

These configurations should make the transition to the new server transparant to the end-user.

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