DNS History - FAQ

Questions:

Q1: Why do I see gaps in the dates for the same record?

Q2: A host name is missing from dnshistory?

Q3: Why do I only see records listed once when they are listed multiple times in the zone file?

Q4: Why do you list (sub)domains that don't exist?

Q5: How often do you check my domains DNS records?

Q6: What is dnshistory-org-wildcard-test?

Answers:

Q1: Why do I see gaps in the dates for the same record?
A1: These could be due to network problems between our server and the domains DNS server, or a problem with the DNS server itself.

Q2: A host name is missing from dnshistory?
A2: We only list host names with characters a-z, 0-9 and '-'. If you still feel we are missing a host name please add it on the index page.

Q3: Why do I only see records listed once when they are listed multiple times in the zone file?
A3: We only list unique records, i.e. if the response for "A" records includes "10.0.0.1, 10.0.0.2, 10.0.0.1" we will only list "10.0.0.1,10.0.0.2" and not the repeated "10.0.0.1" entry.

Q4: Why do you list (sub)domains that don't exist?
A4: We list (sub)domains that are referred to by other domains and this includes those that don't exist (Subject to A2 rules). We also list old (sub)domains that might no longer exist.

Q5: How often do you check my domains DNS records?
A5: We aim to check every domain at least once per month and the minimum interval between checks is 24 hours. We also check the serial provided in the SOA to determine if we need to re-check the other records which really cuts down the number of requests for domains that do not change.

Q6: What is dnshistory-org-wildcard-test?
A6: This is a test hostname we use to help determine if you are using a wildcard (*) in your dns.