Test a public IP address or network for open ports.
Nmap is a powerfully port scanning tool that is online for use by anyone to test Internet facing IP addresses. Only scan systems you have permission to scan. Find open ports in your firewall. A handy tool for network security testing and troubleshooting.
Good options for an online port scanner. Can scan any IP on the Internet and all ports with registration.
Can scan ranges of IP Addresses.
Cons
Results sent to email address.
Summary
Nmap port scanner, with results sent to email address. Scan a range of IP addresses or all ports. Does version detection on open services.
I am using these tools for studying my CEH. External scan from this site and running BackTrack on my computer for local testing.