Longview - Firewall
Just thought I'd share firewall config; from what I can gather in the source code, the only firewall holes required is TCP port 443 to longview.linode.com
iptables -A OUTPUT -p tcp --dport 443 -d longview.linode.com -j ACCEPT
Or an appropriate variation of the above in the FORWARD chain on a perimeter firewall if you have one of them like I do.
That iptables rule looks up longview.linode.com once and stores the IPs (or just one of them?). You're out of luck if the IP changes.
Correct; just like any other iptables rule. You're no better off using the IP address(es) instead of the hostname, and I'm not going to make 443 wide-open. You can if you like.