It works for all traffic - ICMP redirect is only way - how router communicate (letting know - Hey there is better route available for a particular destination) ... So no ip redirects command is related to all IP traffic
There is good article about ICMP redirects
http://support.microsoft.com/kb/195686/EN-US/
If you want disable ICMP redirect on your windows machine (not to accept ICMP redirect from router) try this
http://www.tweakxp.com/article37152.aspx
M.
Hope that helps rate if it does