git throws : "FATAL: You must specify http proxy server"

# git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Cloning into linux-2.6...
FATAL: You must specify http proxy server
fatal: The remote end hung up unexpect开发者_StackOverflow中文版edly

what is the error its been talking about ? though I have the proxy set.

# env | grep -i proxy
http_proxy=http://<ip-address>:80
GIT_PROXY_COMMAND=/root/bin/git-tunnel

however if I use http:// (instead of git://) it works.