HOSTID(1) MachTen Programmer’s Manual HOSTID(1)

NAME
hostid - set or print identifier of current host system

SYNOPSIS
hostid [hexnum or internet address]

DESCRIPTION
Hostid prints the identifier of the current host in hex-
adecimal. This numeric value is expected to be unique
across all hosts and is commonly set to the host’s Inter-
net address. The super-user can set the hostid by giving
a hexadecimal argument or the hostname; this is usually
done in the startup script /etc/rc. In MachTen, hostid is
used to specify which IP address mactcpd will reply with
when a MacTCP application requests a source IP address
before establishing a connection. Since MacTCP is single-
homed, many MacTCP applications assume their source IP
address will not change. In some cases, it may be neces-
sary to set hostid to the source IP address of the network
interface that the MacTCP application will ultimately use
for its connection before launching that MacTCP applica-
tion. Hostid returns the error EPERM if a non root users
tries to set the hostid, or if the IP address specified
does not match any of the available network interfaces.