I have two VPS with 6 IPs and about 20 - 30 websites. The 4 IPs are in same section, other 2 IPs are in another section... I don't know if I place 4-5 sites in one IP is good for seo or not... Or the IP won't hurt SERP that much as I imagine? I think IP should not act a important role in SEO, But I linked my sites cross... For best SEO result, how many sites you placed in one IP? Any suggestions will be much appreciated.
You need not worry about it, because IP plays absolutely no role in SEO. And I think cross linking own sites even do not hurt. Btw, SEO means optimization of web pages to make them use friendly.
IPs really only makes a difference with backlinks. If Google sees many backlinks coming from the same IP then it lowers the link juice that flows