I was able to figure out the issue. On Ubuntu, Docker sets the DNS servers for container to Google’s servers at 8.8.8.x. As I understand it, this is a workaround on Ubuntu due to the fact that Ubuntu sets /etc/resolv.conf to be 127.0.0.1. Those Google servers weren’t accessible from behind our firewall, which is why … Read more
is ‘www’ a normal sub-domain? Yes, it is. From the point of view of DNSs it is a totally normal subdomain. is some special kind of sub-domain? Yes, it is, indeed. It is so commonly used that most Registrars and Hosting providers do automatically create it for you and permanently redirect it to the web … Read more
This is round robin DNS. This is a quite simple solution for load balancing. Usually DNS servers rotate/shuffle the DNS records for each incoming DNS request. Unfortunately it’s not a real solution for fail-over. If one of the servers fail, some visitors will still be directed to this failed server.
Sounds like you’ve done most of the work already. For clarity I’ll go over those steps again just to make sure you’re set up properly: Create an s3 bucket using your domain name as the bucket name (your bucket name should be www.example.com if you want your site to be example.com or www.example.com) Upload your … Read more
I was running into the exact same problem that Saurav described, but I really needed to find a solution that did not require anything other than Route 53 and S3. I created a how-to guide for my blog detailing what I did. Here is what I came up with. Objective Using only the tools available … Read more
The short answer is that it’s usually not possible, unless you control the domain. Option 1: ANY query When you query for ANY, you will get a list of all records at that level but not below. # try this dig google.com any This may return A records, TXT records, NS records, MX records, etc … Read more
Most answers given here are false. It is perfectly legal to have an underscore in a domain name. Let me quote the standard, RFC 2181, section 11, “Name syntax”: The DNS itself places only one restriction on the particular labels that can be used to identify resource records. That one restriction relates to the length … Read more
The hint (using axfr) only works if the NS you’re querying (ns1.foo.example in your example) is configured to allow AXFR requests from the IP you’re using; this is unlikely, unless your IP is configured as a secondary for the domain in question. Basically, there’s no easy way to do it if you’re not allowed to … Read more
You’ll want the SOA (Start of Authority) record for a given domain name, and this is how you accomplish it using the universally available nslookup command line tool: command line> nslookup > set querytype=soa > stackoverflow.com Server: 217.30.180.230 Address: 217.30.180.230#53 Non-authoritative answer: stackoverflow.com origin = ns51.domaincontrol.com # (“primary name server” on Windows) mail addr = … Read more