Keeping the number of internal links on your front page under 100 is essential for the performance of your site. The number of external links is important for your SEO ranking.

You can check both the external and internal links in your pages through a website like the following one:

http://www.linkvendor.com/seo-tools/outbound-links.html

Under Linux you can execute this command in the terminal to find the number of internal and external links:

lynx --dump yourwebsite.tld