BROCADE IP PRIMER

GSLB show CommandsNext, there may be times when you need to override the information in theDNS servers. This is done with the “DNS override” feature. You define a list ofIP addresses to which a given host name should resolve. GSLB will then ignoreresolution information for that host and make its decision from the list you'vedefined:SLB-ServerIron#conf tSLB-ServerIron(config)#gslb dns zone-name brocade.comSLB-ServerIron(config-gslb-dns-brocade.com)#host-info wwwhttpSLB-ServerIron(config-gslb-dns-brocade.com)#host-info www iplist123.123.1.11SLB-ServerIron(config-gslb-dns-brocade.com)#host-info www iplist123.123.1.12SLB-ServerIron(config-gslb-dns-brocade.com)#host-info www iplist123.123.1.13Here, we've defined the standard resolve line “host-info www http,” but we'vealso added an “ip-list” of three additional IP addresses. These addresses willnot be used unless DNS override is enabled. Enable it by entering thiscommand:SLB-ServerIron#conf tSLB-ServerIron(config)#gslb policySLB-ServerIron(config-gslb-policy)#dns overrideAt this point, the resolving for the name “www” will only include the IPaddresses we've defined in the list. The GSLB will use the same appropriatecriteria to decide which IP is listed first.And finally, by default, the ServerIron will forward requests to the DNS server(using SLB, as we defined previously). It is possible to have the ServerIroncache the responses it gets from the DNS server. This will provide an evenfaster response (as the request doesn't have to be forwarded). To enable thisfeature, use the following command:SLB-ServerIron#conf tSLB-ServerIron(config)#gslb policySLB-ServerIron(config-gslb-policy)#dns cache-proxyGSLB show CommandsHere's a list of handy show commands to help you troubleshoot your GSLBconfiguration:• show gslb default — Displays information about the various GSLB policies;specifically, the default configuration of these policies• show gslb policy — Displays the current information about the variousGSLB policies; this should be the same as “show gslb default,” unlesschanges have been madeBrocade IP Primer 399