Cisco Cisco Email Security Appliance C160 Mode D'Emploi
Appendix B Assigning Network and IP Addresses
B-2
Cisco IronPort AsyncOS 7.5 for Email Configuration Guide
OL-25136-01
•
Management
•
Data1
•
Data2
The Cisco IronPort C10/100/150/160 appliance is equipped with two Ethernet
interfaces located on the rear panel of the system. They are labeled:
interfaces located on the rear panel of the system. They are labeled:
•
Data1
•
Data2
Selecting IP Addresses and Netmasks
When you configure the network, the Cisco IronPort appliance must be able to
uniquely select an interface to send an outgoing packet. This requirement will
drive some of the decisions regarding IP address and netmask selection for the
Ethernet interfaces. The rule is that only one interface can be on a single network
(as determined through the applications of netmasks to the IP addresses of the
interfaces).
uniquely select an interface to send an outgoing packet. This requirement will
drive some of the decisions regarding IP address and netmask selection for the
Ethernet interfaces. The rule is that only one interface can be on a single network
(as determined through the applications of netmasks to the IP addresses of the
interfaces).
An IP address identifies a physical interface on any given network. A physical
Ethernet interface can have more than one IP address for which it accepts packets.
An Ethernet interface that has more than one IP address can send packets over that
interface with any one of the IP addresses as the source address in the packet. This
property is used in implementing Virtual Gateway technology.
Ethernet interface can have more than one IP address for which it accepts packets.
An Ethernet interface that has more than one IP address can send packets over that
interface with any one of the IP addresses as the source address in the packet. This
property is used in implementing Virtual Gateway technology.
The purpose of a netmask is to divide an IP address into a network address and a
host address. The network address can be thought of as the network part (the bits
matching the netmask) of the IP address. The host address is the remaining bits of
the IP address. The number of bits in a four octet address that are significant are
sometimes expressed in CIDR (Classless Inter-Domain Routing) style. This is a
slash followed by the number of bits (1-32).
host address. The network address can be thought of as the network part (the bits
matching the netmask) of the IP address. The host address is the remaining bits of
the IP address. The number of bits in a four octet address that are significant are
sometimes expressed in CIDR (Classless Inter-Domain Routing) style. This is a
slash followed by the number of bits (1-32).
A netmask can be expressed in this way by simply counting the ones in binary, so
255.255.255.0
becomes “
/24
” and
255.255.240.0
becomes “
/20
”.