I want to add a forum to the main website and i decided to do it using a subdomain ( forum.site.com ). My question now is, do I need to add another IP to the forum or i can use the main site's IP ( SEO wise ). I don't know if it's better to add a new ip for seo or just to use the same ip the main site has. Any help appreciated
Just use your current websites IP address, there isn't any real SEO value in making a unique IP address on a sub-domain.