Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 31)

Brocade Virtual ADX Global Server Load Balancing Guide 21
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Proxy for DNS server
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This example adds the zone brocade.com and two host names within that zone: www and ftp. The
GSLB Brocade Virtual ADX will provide global SLB for these two hosts within the zone.
Syntax: [no] gslb dns zone-name name
The name parameter specifies the DNS zone name. If you delete a DNS zone (by entering no gslb
dns zone-name name), the zone and all the host names you associated with the zone are deleted.
Syntax: [no] host-info host-name host-application | TCP/UDP-port-num
The host-name parameter specifies the host name. You do not need to enter the entire
(fully-qualified) host name. Enter only the host portion of the name. For example, if the fully
qualified host name is www.brocade.com, do not enter the entire name. Enter only “www”. The rest
of the name is already specified by the gslb dns zone-name command. You can enter a name up to
32 characters long.
The host-application parameter specifies the host application for which you want the GSLB
Brocade Virtual ADX to provide global SLB. You can specify one of the following:
• ftp: the well-known name for port 21. (Ports 20 and 21 both are FTP ports but on the Brocade
Virtual ADX, the name “FTP” corresponds to port 21.)
• tftp: the well-known name for port 69
• http: the well-known name for port 80
• imap4: the well-known name for port 143
• ldap: the well-known name for port 389
• nntp: the well-known name for port 119
• pop3: the well-known name for port 110
• smtp: the well-known name for port 25
• telnet: the well-known name for port 23
The TCP/UDP-port-num parameter specifies a TCP/UDP port number instead of a well-known port.
If the application is not one of those listed above, you still can configure the GSLB Brocade Virtual
ADX to perform the Layer 4 health check on the specified port. If the application number does not
correspond to one of the well-known ports recognized by the Brocade Virtual ADX, the GSLB
Brocade Virtual ADX performs Layer 4 TCP or UDP health checks for the ports but does not perform
application-specific health checks.
Applying GSLB to CNAME records
A Canonical Name (CNAME) record is a type of DNS record that allows network administrators to
create aliases for domain names. For example, an administrator can create the following DNS
records for the Brocade Communications Systems Inc. domain:
• Address record: www.brocade.com, IP address 10.157.22.241
• CNAME record: www.brocade.com, alias for www.brocade.com
A CNAME record refers to another domain name instead of an IP address. A client can enter either
domain name to get to the site. In this example, each domain name goes to site 10.157.22.241.
GSLB supports CNAME records. If you configure domain names that map to other domain names,
the GSLB Brocade Virtual ADX still will perform GSLB for the domain.