DCoda

This plugin is only supported on PHP 5.2 or greater.
 
MembersBlog easily allows you to lock down your blog to members only. 
Unauthenticated visitors who try to view the blog content will be forced to the login page , or presented with an browser login prompt if they try to view the feed.
When the blog and feed are locked down to subscribe to a feed using a feed reader a username and password must be supplied in the url:
<pre><code>http://{username}:{password}@{feed url}
</code></pre>

If you are having trouble and cannot find the answers in the <a href="http://membersblog.dcoda.co.uk/help/faq/" rel="nofollow ugc">FAQ</a> you can post your support questions to the <a href="https://wordpress.org/tags/members-blog" rel="ugc">WordPress Support Forum</a>
If you find MembersBlog useful please rate it at <a href="https://wordpress.org/extend/plugins/members-blog/" rel="ugc">wordpress.org</a> and please consider making a <a href="http://membersblog.dcoda.co.uk/donate/" rel="nofollow ugc">donation</a> to help us set aside more hours to maintain MembersBlog
MembersBlog is written by <a href='http://dcoda.co.uk' rel="nofollow ugc">dcoda</a>
You can check out our other plugins <a href="https://profiles.wordpress.org/users/dcoda/" rel="nofollow ugc">here</a>
If you require a custom plugin you can contact us <a href="http://dcoda.co.uk/contact/" rel="nofollow ugc">here</a> and maybe we could write it for you.
<h3>Copyright</h3>
(c) Copyright DCoda Limited, 2007 -, All Rights Reserved.
This code is released under the GPL license version 2, available here:
<a href="http://www.gnu.org/licenses/gpl.txt" rel="nofollow ugc">http://www.gnu.org/licenses/gpl.txt</a>
There are so many possibly configurations of installation the plugin can be installed on we limit testing to a PHP 5.2+ Linux platform running the latest version of WordPress at the time of release but it is released WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

MembersBlog

Lock down all your posts and pages so only members can access them

Robin W

An add-on to the bbPress forum plugin – creates private forum groups
This Plugin creates unlimited private forum groups.
Forums are then allocated to one or more groups, and users allocated to one or more groups.
What this achieves 
unlimited private groups 
Each user is set to a group or groups, and each forum can have any or all the groups associated with it 
Any number of public forums combined with any number of group forums. The group forums can be individually set to public or private. 
Forum title and description (but not topics or replies) can be set to be visible to non-group users, allowing people to see that a forum exists but not access it 
Separate pages can be set to allow redirection of non group users for sign-up or information 
Topic Permissions 
Topic Permissions is designed for sites where users need to have different permissions to different forums. 
For instance the ability for users to contribute to one forum whilst only being able to view another, or only start topics in one forum, or only reply to topics in another.
Example
So if 
User a belongs to group 1 
User b belongs to group 2 
User c belongs to group 3
and 
Forum x is set to allow group 2 
Forum y is set to allow group 2 and group 3 
Forum z is set to allow group 1 and group 3
Then 
User a can access only forum z 
User b can access forum x and forum y 
User c can access forum y and forum z
Restrictions/warnings
The widgets (bbpress) forums list, (bbpress) recent replies, and (bbpress) recent topics SHOULD NOT BE USED, as they will show topics headings and author names for all forums. Replacement widgets called (private groups) forums list, (private groups) recent replies, and (private groups) recent topics are available instead
Works with bbpress 2.5.3 or higher

Private groups

After wasting hours trying to get Skyverge's WooCommerce Memberships to do what I needed (no practical way to protect topics), I tried this and had it doing everything I needed in under 15 minutes.

Setup a group, manually assigned users to that group.
Set the forum to private and assigned that that group to it.
Viola, everything worked exactly as I wanted.

Public doesn't even see the forum exists. Group members can when logged in.  Non-members can't go directly to to topic URL and bypass the protection.

Only suggestions would be:
1. cleanup the settings pages and instructions, they're a bit overly complicated and hard to follow. 
2. some way to trigger group membership programmatically based on a WooCommerce purchase (I know, to specific and I'll probably code it myself for what I need).

Thanks again for an awesome bbp plugin!

Easy setup and protected forums exactly as I needed

For bbPress - Creates private forum groups

MembersBlog vs Private groups