Host names in the same neighborhood

How do I use "Why Can't I Connect?"

Find all the named devices within an IP address range. This tool uses port connections, the socket function getnameinfo, and, depending on your operating system, ICMP echo requests. These inquiries may be blocked by a firewall and I do NOT try to circumvent these security measures.

Set the range of IP Addresses to be searched (the search range is the last dotted decimal).

Use port connection tests

Initially try to connect to the selected / checked ports while searching for devices in the search range.

Use ports exclusively

Only report devices that have been connected through a selected port.

Predefined ports
AppleTalk (201)

AppleTalk routing maintenance.

AppleTalk (202)

AppleTalk name binding.

AppleTalk (204)

AppleTalk echo.

AppleTalk (206)

AppleTalk zone information.

http (80)

World Wide Web.

https (443)

Secure / SSL http.

ipp / cups (631)

Internet printing protocol / common Unix printing system.

NetBIOS (137)

NetBIOS name service.

NetBIOS (138)

NetBIOS datagram service.

NetBIOS (139)

NetBIOS session service.

nfs (2049)

Network file system.

samba / smb / cifs (445)

Samba / server message block / common internet file system.

snmp (161)

Simple network management protocol.

snmp (162)

Simple network management protocol trap.

ssh (22)

Secure shell.

Custom ports

Add any additional ports to test against.

Windows only
Use ICMP echo request

The socket function getnameinfo may run very slow, depending on your operating system, when a device does not exist on the inquired IP address. Using ICMP echo requests checks the IP address for an existing device before calling the getnameinfo function.


The amount of time in milliseconds that a port connection and an ICMP echo request will wait.