Here’s how to limit access to an IP or subnet on a particular blog on your WordPress MU install:

DISCLAIMER: Modifying .htaccess files can break your WordPress MU install. ALWAYS backup your .htaccess file. Simply, copy .htaccess file and rename it to .htaccess-backup. (cp .htaccess .htaccess-backup)

Step 1:

Add a section after the “RewriteEngine On
RewriteBase /…” section

RewriteCond %{REMOTE_ADDR} !^1\.2\.3\.4
RewriteCond %{REMOTE_ADDR} !^1\.2\.3\.5
RewriteCond %{REQUEST_URI} ^/BLOG1
RewriteRule .* - [F]


DO NOT SAVE YET. You will need edit the IP address info and blog info first:

Step 2: Replace the 1.2.3.4 number with your company IPs (its easier if you have an entire subnet or you can use internal IPs)

For a class C, the part after {REMOTE ADDR} would be
!^1\.2\3\.

Step 3: Replace BLOG1 with the blog you want to limit access to those IPs. So http://www.mysite.com/myfirstblog would be “^/blogs/

Optional: If you have WordPressMU installed in a folder (e.g. not your root folder), you will need to append the directory in front of the blog name.

For instance, if you have http://mysite.com/blog (as your WordPress MU root folder) the ^/ BLOG1 would be

^/blog/BLOG1

Optional: Multiple blogs with same access restrictions
By default, the Apache Rewrite treats every line as an AND statement. If you have multiple blogs, you will need to have an [OR] at the end of the line.

RewriteCond %{REQUEST_URI} ^/BLOG1 [OR]
RewriteCond %{REQUEST_URI} ^/BLOG2

Errors?

• Make sure you have ^/ marks in front of the blog names
• IP addresses must have a backslash before each dot. Regular expression for dot is concatenate by default, so it needs to be escaped
• Make sure you don’t forget the !^ sign before the IP, otherwise you will be forbidden.

If all else fails, if can’t fix the error, just copy back the .htaccess-backup to the .htaccess file.

Highlights of the conference:
Timothy Ferriss, nominated as one of Fast Company’s “Most Innovative Business People of 2007,” is an angel investor and author of the #1 New York Times, Wall Street Journal, and BusinessWeek bestseller, The 4-Hour Workweek, which has been sold into 35 languages. He had a lot of good points on tweaking blogs to reach a larger audience.

WordPress gear! I plan on sending out some stickers and buttons I got at the conference.. stay tuned.

BuddyPress There’s a lot of potential with the community aspect of blogs. I’m hoping this functionality will be integrated with WordPress MU.

Community Speakers and Authors: http://2009.sf.wordcamp.org/speakers/#chris Chris Pirillo is an excellent speaker, had a lot of interesting points about the importance of the community.

http://2009.sf.wordcamp.org/speakers/#tara Tara Hunt’s book about the value of building community vs. buying a community.

http://2009.sf.wordcamp.org/speakers/#cali Cali Lewis (GeekBrief.TV) talked about building an interactive audience. Learned a lot about the challenges of video vs. audio cast.

Last but not least, the community! It was great meeting everyone at the after party.

More info about the upcoming merge with WordPress MU and WordPress (see the comments below the post)
http://technosailor.com/2009/05/30/wordcamp-sf-announcement-wordpress-and-wordpress-mu-to-merge/

By default, the privacy options in WordPress MU is limited to 1) Public, allow search engines 2) Public, don’t allow search engines.

http://wpmudev.org/project/More-Privacy-Options

This plugin adds functionality:
3) I would like my blog to be visible only to registered users from blog community
4) I would like my blog to be visible to registered members of this blog
5) I would like my blog to be visible only to administrators

To install:
1) Download the plugin file.
2) Copy the plugin file to the plugin folder in WordPress MU
3) In the Plugin interface in WordPress MU, activate the “More Privacy Options” Plugin
4) In the Privacy option of the blog (under Settings -> Privacy) you will have the additional privacy options. Select the “I would like my blog to be visible to registered members of this blog
I would like my blog to be visible to registered members of this blog” option.
5) Note: AFAIK, this is on a site by site basis, so will need to enable this plugin for each blog you want to add it to.

Update 4/28/2010:
If you upgrade WordPress MU to a newer version, you will need to set the “Privacy Settings” again. Occasionally, the WordPress upgrade will reset the privacy settings back to default.