Scott Reilly

This plugin records the IP address of the original post author when a post first gets created.
The admin listing of posts is amended with a new “Author IP” column that shows the IP address of the author who first saved the post.
The plugin is unable to provide IP address information for posts that were created prior to the use of this plugin.
Links: <a href="https://coffee2code.com/wp-plugins/post-author-ip/" rel="nofollow ugc">Plugin Homepage</a> | <a href="https://wordpress.org/plugins/post-author-ip/" rel="ugc">Plugin Directory Page</a> | <a href="https://github.com/coffee2code/post-author-ip/" rel="nofollow ugc">GitHub</a> | <a href="https://coffee2code.com" rel="nofollow ugc">Author Homepage</a>
<h3>Hooks</h3>
The plugin is further customizable via four filters. Typically, code making use of filters should ideally be put into a mu-plugin or site-specific plugin (which is beyond the scope of this readme to explain).
c2c_show_post_author_ip_column (filter)
The ‘c2c_show_post_author_ip_column’ filter allows you to determine if the post author IP column should appear in the admin post listing table. Your hooking function can be sent 1 argument:
Argument :
<ul>
<li>$show_column (bool) Should the column be shown? Default true.</li>
</ul>
Example:
<pre><code>/**
 * Don't show the post author IP column except to admins.
 *
 * @param bool $show_column Should the column be shown? Default true.
 * @return bool
 */
function post_author_ip_column_admin_only( $show ) {
 if ( ! current_user_can( 'manage_options' ) ) {
 $show = false;
 }
 return $show;
}
add_filter( 'c2c_show_post_author_ip_column', 'post_author_ip_column_admin_only' );
</code></pre>
c2c_get_post_author_ip (filter)
The ‘c2c_get_post_author_ip’ filter allows you to customize the value stored as the post author IP address. Your hooking function can be sent 2 arguments:
Arguments :
<ul>
<li>$ip (string) The post author IP address.</li>
<li>$post_id (int) The post ID.</li>
</ul>
Example:
<pre><code>/**
 * Store all IP addresses from local subnet IP addresses as the same IP address.
 *
 * @param string $ip The post author IP address.
 * @param int $post_id The post ID.
 * @return string
 */
function customize_post_author_ip( $ip, $post_id ) {
 if ( 0 === strpos( $ip, '192.168.' ) ) {
 $ip = '192.168.1.1';
 }
 return $ip;
}
add_filter( 'c2c_get_post_author_ip', 'customize_post_author_ip', 10, 2 );
</code></pre>
c2c_get_current_user_ip (filter)
The ‘c2c_get_current_user_ip’ filter allows you to customize the current user’s IP address, as used by the plugin. Your hooking function can be sent 1 argument:
Argument :
<ul>
<li>$ip (string) The post author IP address.</li>
</ul>
Example:
<pre><code>/**
 * Overrides localhost IP address.
 *
 * @param string $ip The post author IP address.
 * @param int $post_id The post ID.
 * @return string
 */
function customize_post_author_ip( $ip, $post_id ) {
 if ( 0 === strpos( $ip, '192.168.' ) ) {
 $ip = '192.168.1.1';
 }
 return $ip;
}
add_filter( 'c2c_get_post_author_ip', 'customize_post_author_ip', 10, 2 );
</code></pre>
c2c_post_author_ip_allowed (filter)
The ‘c2c_post_author_ip_allowed’ filter allows you to determine on a per-post basis if the post author IP should be stored. Your hooking function can be sent 3 arguments:
Arguments :
<ul>
<li>$allowed (bool) Can post author IP be saved for post? Default true.</li>
<li>$post_id (int) The post ID.</li>
<li>$ip (string) The post author IP address.</li>
</ul>
Example:
<pre><code>/**
 * Don't bother storing localhost IP addresses.
 *
 * @param bool $allowed Can post author IP be saved for post? Default true.
 * @param int $post_id The post ID.
 * @param string $ip The post author IP address.
 * @return string
 */
function disable_localhost_post_author_ips( $allowed, $post_id, $ip ) {
 if ( $allowed && 0 === strpos( $ip, '192.168.' ) ) {
 $allowed = false;
 }
 return $allowed;
}
add_filter( 'c2c_post_author_ip_allowed', 'disable_localhost_post_author_ips', 10, 3 );
</code></pre>

Post Author IP

Records the IP address of the original post author when a post first gets created.

WP Copy Defender

<h3>SHOW VISITOR IP ADDRESS</h3>
This plugin lets you show the IP address of your visitor using a shortcode or a widget inside posts, pages, or template files.
<h4>SEO-friendly and lightweight code</h4>
This plugin contains lightweight code to be very fast to load, SEO-friendly, and it is developed to have full compatibility with WordPress 3.1 (2011) up to WordPress 5+ (2019), from PHP 5.6 up to PHP 7.3.
<h4>FEATURES:</h4>
<ul>
<li>Show the IP address of your visitor</li>
<li>Easy to use</li>
<li>Lightweight code to quickly load the page and keep a good pagespeed score</li>
<li>No cookies are set by this plugin to visitors</li>
<li>Compatible with all resolutions: desktop, tablet, and smartphones</li>
</ul>
<h4>HOW TO USE:</h4>
You have 2 easy options to have maximum flexibility.
OPTION 1: Use a shortcode
In order to display the output in your specific posts or pages use this code:
<pre><code>[Show_IP title="custom-title"]
</code></pre>
or
<pre><code>[Show_IP]
</code></pre>
In order to display the output in your WordPress template use this code: 
 <code><?php echo do_shortcode( '[Show_IP title="custom-title"]' ); ?></code>
OPTION 2: Use a widget 
Go to Appearance > Widgets and add Show_IP widget where you want to show it.

Show Visitor IP Address – Widget and Shortcode

Display your visitor IP address on posts, pages or template using a widget or a shortcode with this SEO-friendly plugin.

Post Author IP vs Show Visitor IP Address – Widget and Shortcode