IP Services
260
Instruction Manual - NXA-ENET8-POE+
Displaying the DNS Cache
Use the IP Service > DNS - Cache page to display entries in the DNS cache that have been learned via the designated name servers.
Command Usage
Servers or other network devices may support one or more connections via multiple IP addresses. If more than one IP address is
associated with a host name via information returned from a name server, a DNS client can try each address in succession, until it
establishes a connection with the target device.
The following table lists the options on this page:
To display entries in the DNS cache, click Click
IP Service
>
DNS
>
Cache
.
Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol (DHCP) can dynamically allocate an
IP address and other configuration information to network clients when they boot up. If a subnet does not already include a BOOTP
or DHCP server, you can relay DHCP client requests to a DHCP server on another subnet, or configure the DHCP server on this
switch to support that subnet.
When configuring the DHCP server on this switch, you can configure an address pool for each unique IP interface, or manually
assign a static IP address to clients based on their hardware address or client identifier. The DHCP server can provide the host's IP
address, domain name, gateway router and DNS server, information about the host's boot image including the TFTP server to
access for download and the name of the boot file, or boot information for NetBIOS Windows Internet Naming Service (WINS).
Specifying a DHCP Client Identifier
Use the IP Service > DHCP > Client page to specify the DHCP client identifier for a VLAN interface.
Command Usage
The class identifier is used identify the vendor class and configuration of the switch to the DHCP server, which then uses
this information to decide on how to service the client or the type of information to return.
The general framework for this DHCP option is set out in RFC 2132 (Option 60). This information is used to convey
configuration settings or other identification information about a client, but the specific string to use should be supplied
by your service provider or network administrator. Options 60, 66 and 67 statements can be added to the server daemon's
configuration file.
IP Service - DNS (Cache) Options
No.
The entry number for each resource record.
Flag
The flag is always
4
indicating a cache entry and therefore unreliable.
Type
This field includes CNAME which specifies the host address for the owner, and ALIAS which
specifies an alias.
IP
The IP address associated with this record.
TTL
The time to live reported by the name server.
Host
The host name associated with this record.
FIG. 314
Showing Entries in the DNS Cache
Options 60, 66, and 67 Statements
Option
Keyword
Statement Parameter
60
vendor-class-identifier
a string indicating the
vendor class identifier
66
tftp-server-name
a string indicating the tftp
server name
67
bootfile-name
a string indicating the
bootfile name