Unique Ip Hosting Question

[shandaman]

We have aged domains that have had unique ips for some time. Batch 1 average 2 years old and are in 1st to 5th place in their rankings. Batch 2 are 8 months old and not ranking at all. Will there be any issues associated with moving them all to a reseller account with a single ip address?

In addition batch 1 that has good rankings with unique ips is there ever a possibility they will change our ips without notice or for any reason at all that will change and or fluctuate our rankings?

[RyanKent]

Will there be any issues associated with moving them all to a reseller account with a single ip address?

From a ranking perspective, the primary issue would be if the sites link to each other. Links to sites which share an IP are devalued since they are likely under the control of the same party. Search engines have numerous methods to relate sites beyond the IP so if you own a group of sites which link to each other, it is likely search engines may have already devalued any links you created to your other sites.

Another concern of shared IPs is your "neighborhood". If you share an IP with porn sites, gambling sites, hacker sites, etc. it's possible some e-mail systems and companies have banned the IP on their networks which can restrict visitors from accessing your site or cause e-mail to be rejected.

is there ever a possibility they will change our ips without notice or for any reason at all that will change and or fluctuate our rankings?

Your web host owns the IPs assigned to your server so it is possible they could change the IP, but it is not normally done. If it does happen, an IP change should not have any effect on your rankings.