Flushing Stale DNS in Unix

Tell your friends!

In case anyone else needs this information, I’ve just figured out that

ipconfig /flushdns

that we use in the Windows world translates to

lookupd -flushcache

in Unix/Linux/Mac OS X/BSD.

Author: Aaron Brazell

Aaron Brazell is a Baltimore, MD-based WordPress developer, A Sr. Web Enginner at 10up, a co-founder at WP Engine, WordPress core contributor and author. He wrote the book WordPress Bible and has been publishing on the web since 2000. You can follow him on Twitter, on his personal blog and view his photography at The Aperture Filter.

  • http://www.homelandstupidity.us/ Michael Hampton

    It does?

    I certainly don’t have any “lookupd” on any of my Linux boxes.

    As far as I know, Linux (and most other Unix variants) doesn’t cache DNS lookups at all; however, individual applications might do so. Firefox is notorious for this.

  • http://www.technosailor.com/the-technosailor/ Aaron Brazell

    Yeah and actually it’s on CentOS as well as OS X. I’ve used it quite a bit recently. Generally the times I need it come when I start hardcoding /etc/hosts to migrate blogs, etc. Happens in Firefox and Safari, so… yeah. :)

  • http://mjr.towers.org.uk/ MJR/slef

    So how does that differ from rndc flush?

  • http://www.technosailor.com/the-technosailor/ Aaron Brazell

    Not saying it is different. It’s just how I do it.

  • http://www.homelandstupidity.us/ Michael Hampton

    rndc flush deals with the nameserver itself, not the workstations which use the nameserver.

    In any case, I still haven’t even been able to FIND a lookupd on CentOS. What package is it in?

    It certainly sounds like you’re doing absolutely nothing — or something quite different from Windows.

  • http://www.technosailor.com/the-technosailor/ Aaron Brazell

    Michael, you’re right. My bad. I thought I had used it on our servers but I hadn’t and it’s not on Linux (will update entry). It’s a BSD sysutil (and thus on OS X).