IPv6 addresses are not allowed in this field. IPv6 address is not well formed. IPv4 addresses are not allowed in this field. IPv4 address is not well formed. Must be a valid IP address. Field contains illegal characters. Port number cannot start with a zero (0). Must be a decimal number. Service name not recognised; consult /etc/services for a list. Must be ≤ 65535. Must be ≥ 1024. Clashes with a common port (such as ssh or http).