User Manual

IP IP Addresses
6-3
To avoid routing and security problems, the SCS should restrict incoming callers to a particular address or
range of addresses. This restriction may be defined in each site to force each caller to use a unique IP
address; see Specifying a Site’s IP Address Range on page 6-3 for configuration instructions.
6.1.1.1 Defining an IP Address Pool
An address pool is a range of IP addresses that have been reserved for allocation to incoming callers. The
range is defined for the entire server; in other words, an address pool cannot be defined for each site.
To define an address pool, use the Set/Define IP Ethernet Pool command. You must specify both the
beginning and end of the address range.
Figure 6-1: Defining an IP Address Pool
Note: Set/Define IP All Pool is not a valid command. The Ethernet parameter must be
used.
Ensure that the address pool is at least as large as the number of serial ports that can accept incoming
connections. If all addresses in the pool are in use, incoming callers will not be assigned an IP address.
The SCS will automatically add host routes to the routing table for all addresses in the pool. When an
address from the pool is assigned to an incoming caller, the route to the address will be announced in RIP
broadcasts.
Addresses in the pool are automatically added to the SCS ARP table. If proxy ARPing is enabled (see Proxy
ARP on page 6-18), the SCS will respond to ARP requests for these addresses, even when they aren’t
currently assigned. This enables the SCS to defend the addresses in the pool; other hosts will not be able to
use them.
6.1.1.2 Specifying a Site’s IP Address Range
Each site may specify a particular range of acceptable IP addresses. When an incoming caller requests to
use a specific address, it will be compared to this range. If the address falls within this range, the connection
will be permitted; if not, the connection attempt will fail.
To specify the beginning and end of the range, use the Define Site IP Remoteaddress command. Two
addresses must be specified: the beginning of the range and the end of the range.
Figure 6-2: Specifying a Range of Addresses
Callers will not be permitted to use IP addresses with the host part of the address set to zero or -1. These
addresses are reserved to identify broadcast packets. If the range that you specify includes such an address
(for example, 192.5.6.0 or 192.4.2.255) and a caller requests this address, the connection will not be
permitted.
RADIUS can also be used to set the IP address range for a site. See Framed-IP-Address on page D-3 for
more information.
Local>> DEFINE IP ETHERNET POOL 192.0.1.50 192.0.1.59
Local>> DEFINE SITE irvine IP REMOTEADDRESS 192.0.1.110 192.0.1.250