does keep-alive rely on server:port or ip:port?

just a quick question

[Xuefer]

ie/mozilla and opera etc..
do they use keep-alive rely on server:port or ip:port?

and how many connections does those browser open? "for 1 host" and "at total"

[Dreamquick]

AFAIK the keep alive applies to the connection so its it will be whatever IP they connected to in this instance, the point of keep alive is that it keeps one connection alive for several requests which saves time for the client and resources for the server.

- Tony