wp_rel_nofollow() does this for you. It is already called on pre_comment_content, so comments should be covered. For sidebars and footers, this depends on the widgets and other code you use there, but it should be possible to call that function there too.
Related Posts:
- Get parent page url to show up when it is in child pages
- Why is there a link tag with rel “profile” pointing to gmpg.org?
- How to use wpLink without editor?
- Add CSS Class to Link in TinyMCE editor
- How to print translation supported text with HTML URL
- Get the prev / next page links only (not title, etc)
- How to re-enable the links manager?
- Wondering how to turn your firefox bookmarks into a WordPress blog?
- How can I link to the most recent post in a category?
- Links redirecting to localhost after migration to server
- Is it possible to link to draft pages?
- How can I find all internal links that are pointing to post/page?
- Creating a Link Directory using WordPress?
- Count and show Clicks on external links in a single page/post
- How to use wp_rel_nofollow to add nofollow to external links only?
- get_category_link() is returning nothing
- Is there any way to set default for “Insert/Edit Link” to “Open link in new window”?
- root-relative links for multiple parked domains
- Get link value only from the_content()?
- How to splice in wp_links links into the loop?
- widget to output a link to archive view
- Is there an easy way to create a links index page?
- Can’t add a class to links in the visual editor since WP 3.1?
- What is the canonical way to link to pages?
- how can i add a menu link that goes to an external page
- Remove all links to a specific website
- HTTPS page link in menu
- How do I remove or disable “Or link to existing content” in “insert link” dialogue?
- Retrieving all Links from a Post?
- Link Category Description
- Auto-embed link info from URLs in link post format?
- programatically change href to onclick=window.open
- Disable automatic content hyperlinking
- Open link in a new tab checked by default when adding a new link in visual post editor
- Deep linking to an accordion tab with Visual Composer
- Setting a page link in the footer?
- How to add/change a value of $wpdb property/var?
- Need advice on how to add links in users profile page?
- Generate Random Post Links Somewhere in the post
- How to hide a customization link themes menu in wordpress?
- Getting only the most recent bookmark?
- WordPress links/bookmarks – need to urlencode because spaces are getting stripped
- Custom Post Type archive link in WYSIWYG editor
- Add Link Text Back to Insert/edit link Box
- How to list all external URLs that I have posted on my WordPress blog?
- How do I make my navigation bar link to an external page?
- Plugin that inserts favicon next to links
- Create anchor from Wysiwyg editor
- Is there any way of changing the post order via user click?
- Get post / page ID from ACF Link field
- Creating a navigation link to my front-page
- How to remove author name and link from a shared link preview?
- wp_get_attachment_link to add title attribute to link tag around image
- Can I generate then display a mixed list of linked and unlinked terms
- Relative links for performance?
- Make page tab link to pdf
- Dont’t change active Button while I’m listing a category?
- How to change server name on WordPress Installation?
- How to prevent a page from being linked in the menu/crossbar
- How do i set the read more link?
- Plugin for wikipedia style references in WP?
- Problem creating an edit link for a custom post type
- Linking from Menu and a Page to the latest post from a specific category
- After duplicating site to a sub folder, links send user to original site
- Automaticly replace a link with other “new link”
- Links are not working on All Plugins Page
- How to add a WordPress page with multiple picture links?
- Enumerating over a category of links
- Is there a way to hide WordPress behind a web visible directory?
- Twitter links in widget don’t work?
- Links in nonalphabetic order
- Copy button for anchor link
- How to automatically nofollow a set domains? (I seem to have half of the answer)
- WordPress links https overwrite issue
- My custom link works only on home page
- Read more link to external webpage
- plugin admin subpage title and links in menu not highlited at current page
- Change Read More in Child theme
- Add text excerpt and pictures to hyperlinks?
- Default Link for TinyMCE “Add Link”
- WordPress changes URL?
- How to apply default post categories to link manager plugin
- Parent/child pages and link structure the right way
- How do I get link URLs from the WordPress links backend into an array?
- Link below the footer removal
- How to change all external links to “nofollow” but only for Contributor role?
- Is there anyway to use relative link instead of absolute link?
- How to link to local post
- How can I show different image links for different languages with qTranslate?
- How do I hide the ‘Edit’ link in publshed posts
- Exclude uploaded files from appearing in the excerpt()
- link to single most recent post, regardless of category
- Change description of my Jetpack facebook shared links [closed]
- Do you use links?
- WP Method `get_theme_file_uri()` Doesn’t Seem To Be Working Properly When Used In The Head Section Of A Site
- Add the title attribute to links
- Moving a wordpress.org website to another domain name?
- WordPress relative links for regular non image links
- how do I get rid of the links and all the links related menu items on the admin ui?
- How do I make WordPress “Page” link in the top nav bar go to an external URL?