Category: DNS

DNS Firewalls
11 June 2022

Call the DNS Doctor

I never really knew DNS doctoring was much of a thing until I encountered it: essentially getting your firewall to alter or doctor DNS responses. One use case for this might be that you can have your internal hosts receive an internal DNS address whilst keeping them pointing to an external ISP’s DNS. I could go on but somebody already has: https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/115753-dns-doctoring-asa-config.html So I thought […]

DNS
20 March 2022

CNAME of shame

Before I left work on Friday some of our proxies were showing a DNS error getting to https://app.powerbi.com our MSP was left pursuing this. I decided to do a bit of digging myself. A DNS query can provide an ‘A’ response which tells the querier the ip address associated with the given name, but often a CNAME record can be returned (Canonical Name) which effectively […]

DNS
15 November 2020

Barefaced Cheek

I was messing around with various things when I had cause to check the address of this website and found I was getting a different ip address for www.labtinker.net and labtinker.net.  This should not happen because www.labtinker.net has a DNS CNAME record which points to labtinker.net And this in turn points to the ip address of the website: So both these URLs should ultimately point […]