How to check MX records

First you can check that the declaration is correct, using dig:

# dig MX

; <<>> DiG 9.7.3 <<>> MX
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32034
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;                    IN      MX

;; ANSWER SECTION:             14400   IN      MX      0

;; ADDITIONAL SECTION:             14400   IN      A

;; Query time: 198 msec
;; WHEN: Fri Jun 23 18:56:51 2017
;; MSG SIZE  rcvd: 60

Next you can use an online tool, like mxtoolbox to check others requirements and make sure the server's IP isn't already included into a commonly use blacklist.

Fallacies of distributed computing

The fallacies of distributed computing are a set of assertions made by L Peter Deutsch and others at Sun Microsystems describing false assumptions that programmers new to distributed applications invariably make.