Rackspace yum install git cURL 443 Connection refused

the easy answer: give us a call or submit a ticket and we can look at your firewall to see what's going on.

the DIY answer: since you can reach "https://github.com" but not "https://rhui.rackspace.com", you might have outbound firewall rules configured, or servers at "rhui.rackspace.com" aren't behaving.

check your outbound firewall rules. For either case below, you'll want to permit traffic to the destination host (rhui.rackspace.com) on destination port 443 with protocol TCP

1. software firewall
   for firewalld or iptables, try sudo iptables -vnL OUTPUT and look for "policy ACCEPT" (the default)

2. hardware firewall
   in the MyRackspace portal under Network > Firewall Manager V2, look for the sections 100, inside, or FW-INSIDE ACL which cover outbound traffic