Tag Archives: DNS

Sysadmin: how to test your web site before switching DNS

How to test your web site after moving it to the new location, before switching DNS and “going live” there? This situation happens every day, even multiple times a day with single page placeholder sites and huge complicated web portals. I thought I’ll just put together simple instruction to refer people to it instead of explaining it over and over every time.
So, in order to test your web site on the new server, before switching DNS settings to the new location you will need to fool your desktop browser to look into new IP location. Here is how to do it.
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Centos: How to configure DKIM for sendmail on multiple domains

dkim I wanted to configure DKIM for sendmail on multiple domains for one of the dedicated servers and found out that there are no usable instructions for CentOS and few that are available are inconclusive (I will provide the list of information sources at the end of this post). Here is my tested working setup:
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Sysadmin: block these pesky recursive DNS queries with iptables rate limiting rules

dns-reflectIf you are managing Linux server you have probably heard about recent DNS amplification attacks that were using misconfigured DNS servers.
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Hosting: Howto redirect domain to another domain.

There is always a question on how to completely redirect some src-domain to another dst-domain properly.
And while there is the simple straightforward way to do so, there are always some dedicated server customers of the web hosting that are trying to reinvent the wheel one more time. And failing miserably.
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Sysadmin shell oneliner: update serial in all DNS zones

Sometimes you just need to force updates on slave DNS servers. The easiest way to do it is to increase zone serials on master server. what if there are hundreds of zone files? Here is one way to do it
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