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JSC's avatar
JSC
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Dec 11, 2017

Strange behavior with "DNS::is_wideip" command

We are issuing a strange behavior with the command "DNS::is_wideip".

Documentation say '''This iRules command returns status (true/false) if a string is a configured wide IP. (https://devcentral.f5.com/wiki/irules.dns__is_wideip.ashx)

We declared the wideip 

mydnsalias.domain.com
.

And the iRule:

when DNS_REQUEST {``  
  if { not [DNS::is_wideip [DNS::question name]] } {
    switch -glob [string tolower [DNS::question name]] {
      "a.customdns.name" { }
      default { 
        log local0.info "[DNS::question name] drop" 
        DNS::drop
      }
    }
  }      
}

It works, however we have a lot of log with:

Rule /Common/GTM_FILTER_DOMAIN_IRULE : mydnsalias.domain.com drop

Any clue why the condition is not "always" satisfied?

application delivery
BIG-IP DNS
  • JSC's avatar
    JSC
    Icon for Nimbostratus rankNimbostratus
    Dec 11, 2017

    Adding more logs:

    log local0.info "isWideIP '[DNS::question name]'? -> '[DNS::is_wideip [DNS::question name]]'"

    Here what we got:

    Dec 11 11:39:09  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '0'
Dec 11 11:39:09  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '0'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '0'
Dec 11 11:39:10  info tmm[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '0'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '1'
Dec 11 11:39:10  info tmm1[10927]: Rule /Common/GTM_FILTER_DOMAIN_IRULE : isWideIP 'mydnsalias.domain.com'? -> '0'

    Note: when it happens, it seems to be one in two...