trying to add an hyperlink as http://10.xx.xx.xxx to a text on blog post or in forum, link it snot rendering .
is there any way we can allow ip address also as hyperlinks.
Internal IPs can be used for phishing attacks and do not link by default. You have options and know your community best so can choose what fits. Generally speaking the recommendation is to narrow the surface (ips) as much as possible if you can. There are two levels of ip content filtering configuration in Community, site and content. The site level always enables what is possible, but the content can further restrict.
1. (Most secure) Whitelist the IPs using the site "Filtering" options - When configured at the site level, these IPs are now allowed across all content that support filtering (comments, blog posts, forum thread, replies, etc). If you want to allow only to blogs to use these IPs you mustopt out of allowing these API at the content level for any of the other applications (Administration-> Applications -> Content -> [pick the content type] -> Filtering tab).
2. Enable any internal IP to bloggers - Using the same configuration location as above, check the "Allow local network addresses". Similiar to above, you can optionally further restrict internal IP usage to just bloggers by disabling the option for other content (ex. converstation messages, comments, forum thread, forum replies, etc).
Note: Non-local IPs also can be enable/disabled. In all cases if an IP based url is used link text is always displayed (as you have seen) so no information is lost.