Flushing DNS cache

We recently had a customer who needed an update to DNS, and it was taking a very, very long time to propagate. While researching how to help fix it, I found these sites that may come in handy.

To see what’s going on with DNS propagation, use this tool: What Is My DNS

And if you ever need to check a particular DNS server’s entries, use this: Query a DNS Server

Plus a very handy page describing how to use nslookup: 10 Most Used nslookup Commands

Redirecting attachment pages in WordPress

Spammers are a crafty bunch, using a variety of techniques to spread their unwanted junk. One way they do this is by submitting comments to the special pages WordPress creates for each image that has been uploaded. Spammers find these pages and submit spam. But there are ways to thwart their misdeeds!

7 Ways to Redirect WordPress Attachment Pages

Lately we’ve been using the Redirect Attachment Pages plugin, if the client does not have it available through an SEO plugin.

Finding large files on Linux

I had a client running out of disk space, and support gave me the command to find all the big stuff. This is to find files larger than 10MB. It prints a list ordered by smallest to largest.

sudo find / -mount -noleaf -type f -size +10000k -print0 | xargs -0 ls -lhSr | perl -ne ‘/(\S+\s+){4}(\S+)\s+(\S+\s+){3}(.*)/ and printf(“%*s %s\n”,7,$2.”:”,$4);’

One thing to note is that this didn’t include mailboxes… they must be stored somewhere else on this particular server. The culprit in this case turned out to be a mailbox that was 15GB (!!).