User's Manual

Chapter 12 Interfaces
ISG50 User’s Guide
243
MTU Maximum Transmission Unit. Type the maximum size of each data packet, in bytes, that
can move through this interface. If a larger packet arrives, the ISG50 divides it into
smaller fragments. Allowed values are 576 - 1500. Usually, this value is 1500.
Connectivity Check These fields appear when Interface Properties is external.
The interface can regularly check the connection to the gateway you specified to make
sure it is still available. You specify how often the interface checks the connection, how
long to wait for a response before the attempt is a failure, and how many consecutive
failures are required before the ISG50 stops routing to the gateway. The ISG50
resumes routing to the gateway the first time the gateway passes the connectivity
check.
Enable
Connectivity
Check
Select this to turn on the connection check.
Check Method Select the method that the gateway allows.
Select icmp to have the ISG50 regularly ping the gateway you specify to make sure it is
still available.
Select tcp to have the ISG50 regularly perform a TCP handshake with the gateway you
specify to make sure it is still available.
Check Period Enter the number of seconds between connection check attempts.
Check Timeout Enter the number of seconds to wait for a response before the attempt is a failure.
Check Fail
Tolerance
Enter the number of consecutive failures before the ISG50 stops routing through the
gateway.
Check Default
Gateway
Select this to use the default gateway for the connectivity check.
Check this
address
Select this to specify a domain name or IP address for the connectivity check. Enter that
domain name or IP address in the field next to it.
Check Port This field only displays when you set the Check Method to tcp. Specify the port
number to use for a TCP connectivity check.
DHCP Setting These fields appear when Interface Properties is Internal or General.
DHCP Select what type of DHCP service the ISG50 provides to the network. Choices are:
None - the ISG50 does not provide any DHCP services. There is already a DHCP server
on the network.
DHCP Relay - the ISG50 routes DHCP requests to one or more DHCP servers you
specify. The DHCP server(s) may be on another network.
DHCP Server - the ISG50 assigns IP addresses and provides subnet mask, gateway,
and DNS server information to the network. The ISG50 is the DHCP server for the
network.
The following fields appear if the ISG50 is a DHCP Relay.
Relay Server 1 Enter the IP address of a DHCP server for the network.
Relay Server 2 This field is optional. Enter the IP address of another DHCP server for the network.
The following fields appear if the ISG50 is a DHCP Server.
IP Pool Start
Address
Enter the IP address from which the ISG50 begins allocating IP addresses. If you want
to assign a static IP address to a specific computer, use the Static DHCP Table.
If this field is blank, the Pool Size must also be blank. In this case, the ISG50 can
assign every IP address allowed by the interface’s IP address and subnet mask, except
for the first address (network address), last address (broadcast address) and the
interface’s IP address.
Table 65 Configuration > Network > Interface > Ethernet > Edit (continued)
LABEL DESCRIPTION