4 ms·

Slightly related: There used to be a DNS server that you could query a TXT record and the response would include the IP of the server that submitted the query.

by dfc 3y ago

Slightly related: There used to be a DNS server that you could query a TXT record and the response would include the IP of the server that submitted the query. You could use it to debug DNS issues. I thought it was from DNS-OARC but I can't find it anywhere. Does anyone know a way to accomplish this?

erinnh 3y ago
I don’t know of a server that does exactly what you wrote, but I generally troubleshoot dns issues with a few dig commands. dig without any parameters will resolve via your normal dns server and display the servers ip. With @(dns server ip here) you can query a different dns server to check what their answer is. With +trace you can go through the complete dns chain from the root servers on to check for issues in the chain. Sorry if this doesn’t help you or you knew this already.
gavinsyancey 3y ago
dig +short TXT o-o.myaddr.l.google.com @ns1.google.com
- deleted 3y ago
  [deleted]
- dfc 3y ago
  This works! Thank you very much.
thenickdude 3y ago
I believe you're thinking of OpenDNS: dig -4 +short myip.opendns.com @resolver1.opendns.com
- jtokoph 3y ago
  And the v6 version: dig -6 +short myip.opendns.com @resolver1.opendns.com aaaa
- dfc 3y ago
  This only seems to work if your client can send requests directly to resolver1.opendns.com. It does not work if you have a server that is intercepting DNS or if you use the system configured DNS. The google version posted below is closer to what I was looking for: $ dig +short TXT o-o.myaddr.l.google.com @ns1.google.com "A.B.C.D" $ dig +short TXT o-o.myaddr.l.google.com "172.253.195.202" "edns0-client-subnet A.B.C.0/24" $ dig +short TXT o-o.myaddr.l.google.com @9.9.9.9 "162.244.55.23" $ dig +short TXT o-o.myaddr.l.google.com @1.1.1.1 "172.71.221.175" The opendns implementation returns nothing if you try something similar to the last three.
  - arjvik 3y ago
    There's a whole list of such resolvers: Akamai: dig +short whoami.akamai.net @ns1-1.akamaitech.net Google: dig +short o-o.myaddr.l.google.com txt @ns1.google.com Cloudflare: dig +short whoami.cloudflare ch txt @1.1.1.1 OpenDNS: dig -4 +short myip.opendns.com @resolver1.opendns.com Note that if you leave off the `@service.authoritative.nameserver` portion of all of the above, you get the IP address of the recursive resolver that your machine is configured to use. If you pass this to a service like https://ipinfo.io/ https://ipinfo.io/, you can use this to figure out what company's DNS service is currently configured, be it your ISPs, or an internet company like Cloudflare/Google/Quad9. Arguably, that is the only valid reason to be using an IP address echoer via DNS, as if you truly wanted your own IP, you could fetch it far easier from a service like icanhazip.com. Personally, Akamai's offering is by far the most useful and convenient--it's an A record, so you won't accidentally forget to add "txt" to your dig invocation, and has a very easy to remember name. Google's works too, though it requires remembering the strange domain name. Cloudflare tries to be cute and uses the Chaosnet DNS class, which while being an incredibly cool reference to internet history, unfortunately is not propagated by most public recursive resolvers. And like the parent comment mentions, OpenDNS somehow blocks requests that pass through a recursive resolver.
    - dfc 3y ago
      The opendns server does not return anything if I send the query to anything other than opendns.
p1mrx 3y ago
"https://myresolver.info/ https://myresolver.info/" was good while it lasted. It used stupid DNS tricks to show your resolver in the browser: https://web.archive.org/web/20131126131155/https://ndkyez8khir.target.myresolver.info/ https://web.archive.org/web/20131126131155/https://ndkyez8kh...
mgbmtl 3y ago
You could write a program that listens on port 53, parses the query and returns the correct value? DNS is hard to implement, but for responding to a very specific type of query, should be easy?
theblazehen 3y ago
In addition to the others, there is also https://www.dns.toys/ https://www.dns.toys/

by dfc 3y ago

erinnh 3y ago

I don’t know of a server that does exactly what you wrote, but I generally troubleshoot dns issues with a few dig commands. dig without any parameters will resolve via your normal dns server and display the servers ip. With @(dns server ip here) you can query a different dns server to check what their answer is. With +trace you can go through the complete dns chain from the root servers on to check for issues in the chain. Sorry if this doesn’t help you or you knew this already.

gavinsyancey 3y ago

dig +short TXT o-o.myaddr.l.google.com @ns1.google.com

deleted 3y ago
[deleted]
dfc 3y ago
This works! Thank you very much.

thenickdude 3y ago

I believe you're thinking of OpenDNS: dig -4 +short myip.opendns.com @resolver1.opendns.com

jtokoph 3y ago
And the v6 version: dig -6 +short myip.opendns.com @resolver1.opendns.com aaaa
dfc 3y ago
This only seems to work if your client can send requests directly to resolver1.opendns.com. It does not work if you have a server that is intercepting DNS or if you use the system configured DNS. The google version posted below is closer to what I was looking for: $ dig +short TXT o-o.myaddr.l.google.com @ns1.google.com "A.B.C.D" $ dig +short TXT o-o.myaddr.l.google.com "172.253.195.202" "edns0-client-subnet A.B.C.0/24" $ dig +short TXT o-o.myaddr.l.google.com @9.9.9.9 "162.244.55.23" $ dig +short TXT o-o.myaddr.l.google.com @1.1.1.1 "172.71.221.175" The opendns implementation returns nothing if you try something similar to the last three.
- arjvik 3y ago
  There's a whole list of such resolvers: Akamai: dig +short whoami.akamai.net @ns1-1.akamaitech.net Google: dig +short o-o.myaddr.l.google.com txt @ns1.google.com Cloudflare: dig +short whoami.cloudflare ch txt @1.1.1.1 OpenDNS: dig -4 +short myip.opendns.com @resolver1.opendns.com Note that if you leave off the `@service.authoritative.nameserver` portion of all of the above, you get the IP address of the recursive resolver that your machine is configured to use. If you pass this to a service like https://ipinfo.io/ https://ipinfo.io/, you can use this to figure out what company's DNS service is currently configured, be it your ISPs, or an internet company like Cloudflare/Google/Quad9. Arguably, that is the only valid reason to be using an IP address echoer via DNS, as if you truly wanted your own IP, you could fetch it far easier from a service like icanhazip.com. Personally, Akamai's offering is by far the most useful and convenient--it's an A record, so you won't accidentally forget to add "txt" to your dig invocation, and has a very easy to remember name. Google's works too, though it requires remembering the strange domain name. Cloudflare tries to be cute and uses the Chaosnet DNS class, which while being an incredibly cool reference to internet history, unfortunately is not propagated by most public recursive resolvers. And like the parent comment mentions, OpenDNS somehow blocks requests that pass through a recursive resolver.
  - dfc 3y ago
    The opendns server does not return anything if I send the query to anything other than opendns.

p1mrx 3y ago

"https://myresolver.info/ https://myresolver.info/" was good while it lasted. It used stupid DNS tricks to show your resolver in the browser: https://web.archive.org/web/20131126131155/https://ndkyez8khir.target.myresolver.info/ https://web.archive.org/web/20131126131155/https://ndkyez8kh...

mgbmtl 3y ago

You could write a program that listens on port 53, parses the query and returns the correct value? DNS is hard to implement, but for responding to a very specific type of query, should be easy?

theblazehen 3y ago

In addition to the others, there is also https://www.dns.toys/ https://www.dns.toys/