Enhanced Host Name Resolution
From OPC Labs Knowledge Base
In some scenarios, the host names listed in the tables below are recognized in addition to normal (system) host resolution process. For performance reasons (because the normal host resolution can take considerable time), the enhanced host name resolution takes place first; that is, if the host name is one of those listed in the corresponding table, it is resolved using the enhanced host name resolution table, and the normal host name resolution will not take place.
Depending on the context, the program might be resolving the host name either to IP address or to the MAC (physical) address. A different set of host names is recognized in each case.
Resolution To IP Address
| Host Name | IPv4 Address | IPv6 Address |
|---|---|---|
| broadcasthost | 255.255.255.255 | |
| ip6-allhosts | ff02::3 | |
| ip6-allnodes | ff02::1 | |
| ip6-allrouters | ff02::2 | |
| ip6-localhost | ::1 | |
| ip6-localnet | fe00::0 | |
| localhost | 127.0.0.1 | ::1 |
| localhost.localdomain | 127.0.0.1 | ::1 |
| localhost4 | 127.0.0.1 | |
| localhost4.localdomain4 | 127.0.0.1 | |
| localhost6 | ::1 | |
| localhost6.localdomain6 | ::1 |
When used:
- OPC UA PubSub connection resource URIs with scheme "opc.udp".
Resolution To MAC Address
| Host Name | MAC Address |
|---|---|
| eth-broadcast | FF-FF-FF-FF-FF-FF |
When used:
- OPC UA PubSub connection resource URIs with scheme "opc.eth".
