Add Resolve The Public IP Of A URL as a devops til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_805 TILs and counting..._
+_806 TILs and counting..._
 
 ---
 
@@ -113,6 +113,7 @@ _805 TILs and counting..._
 - [Path Of The Packets](devops/path-of-the-packets.md)
 - [Push Non-master Branch To Heroku](devops/push-non-master-branch-to-heroku.md)
 - [Reload The nginx Configuration](devops/reload-the-nginx-configuration.md)
+- [Resolve The Public IP Of A URL](devops/resolve-the-public-ip-of-a-url.md)
 - [Running Out Of inode Space](devops/running-out-of-inode-space.md)
 - [Wipe A Heroku Postgres Database](devops/wipe-a-heroku-postgres-database.md)
 

devops/resolve-the-public-ip-of-a-url.md

@@ -0,0 +1,38 @@
+# Resolve The Public IP Of A URL
+
+The `dig` command is a utility for doing DNS lookups. You can run it with a
+URL argument to lookup the public IP for that domain.
+
+```bash
+$ dig joshbranchaud.com
+
+; <<>> DiG 9.8.3-P1 <<>> joshbranchaud.com
+;; global options: +cmd
+;; Got answer:
+;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 62836
+;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
+
+;; QUESTION SECTION:
+;joshbranchaud.com.             IN      A
+
+;; ANSWER SECTION:
+joshbranchaud.com.      1800    IN      A       159.203.106.229
+
+;; Query time: 50 msec
+;; SERVER: 75.75.75.75#53(75.75.75.75)
+;; WHEN: Sun Apr 14 12:34:52 2019
+;; MSG SIZE  rcvd: 51
+```
+
+The output is a bit noisy, but if you parse down to the _ANSWER SECTION_,
+you'll see the IP address that it resolves to.
+
+Alternatively, you can skip the noise and get right to the IP address by
+including the `+short` flag.
+
+```bash
+$ dig joshbranchaud.com +short
+159.203.106.229
+```
+
+See `man dig` for more details.