Lucent Technologies PortMaster 4, Configuration Manual

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Configuring Global Settings 2-7
Configuring Local IP Addresses
With the local IP address feature, you can specify the Ethernet interface the PortMaster
uses as the default service address. For example, if RADIUS and the Signaling
System 7 (SS7) gateway are on a private network range attached to Ether0, you can use
the Ether0 address as the first local IP address.
IPCP Negotiation
During PPP negotiations for the IP Control Protocol (IPCP), the PortMaster 4 uses the
following order of precedence when choosing an IP address to identify itself:
1. The Local IP address configured in the user profile, if set
2. The global reported IP address, if set
3. The first global local IP address, if set
4. The second global local IP address, if set
5. The third global local IP address, if set
6. The fourth global local IP address, if set
7. The IP address of Ether1
8. The IP address of Ether0
Main IP Address
When the PortMaster creates an IP packet, it must identify itself by placing a source
address in the IP header. To do so, the PortMaster chooses either the main IP address or
the nearest IP address, depending on the service used. The main IP address is chosen in
the following order, but the nearest IP address is the IP address of the interface on which
the packet exits the PortMaster 4:
1. The first global local IP address, if set
2. The second global local IP address, if set
3. The third global local IP address, if set
4. The fourth global local IP address, if set
5. The IP address of Ether1
6. The IP address of Ether0
The following services use the main IP address:
• syslog
• traceroute
• telnet
• DNS