Scheduling

Round Robin

This is the same principle as the normal LoadMaster with one exception - when using the nslookup command, by default, it checks for both IPv4 (A) records and IPv6 (AAAA) records, which actually sends out two requests.

If you have two sites:

  • Request 1 - IPv4 A round robin to Site 1
  • Request 2 - IPv6 AAAA round robin to Site 2
  • Request 3 - IPv4 A round robin to Site 1
  • Request 4 - IPv6 AAAA round robin to Site 2

When testing, clients looking for IPv4 always connect to Site 1 and clients looking for IPv6 always connect to Site 2. To help prevent this from occurring during testing, you can add an odd number of sites.

nslookup Troubleshooting

nslookup command:

c:\> nslookup <FQDN> <GEO address>

For example:

c:\> nslookup geotest.lan 10.113.0.52

Response is:

Name: geotest.lan
Address: 10.10.10.10

Commands for further testing:

Changes request type to IPv4 A record:

nslookup –query=A

Changes request type to IPv6 AAAA record:

nslookup –query=AAAA

DIG command:

user@linux: dig <domain>
user@linux: dig test.domain.com

Search for an FQDN:

user@linux: dig –t <record type> <FQDN>
user@linux: dig –t A test.domain.com

Search for an A record type:

user@linux: dig –t <record type> <FQDN>
user@linux: dig –t AAAA test.domain.com

Search for an AAAA record type:

user@linux: dig –t A <DNS server/ GEO> <domain>
user@linux: dig –t A @10.113.0.54 test.domain.com

Search for an A record type against this DNS server or GEO (10.113.0.52).