If you also have to make frequent DNS queries to the MX records or SPF and reverse records, this little script may help:
Test-MXSettings.ps1
The script has a few parameters, which can quickly check all Exchange accepted domains, or any domain, also a DNS server for the query can be specified. The following parameters are possible:
-test domain : Checks a domain
-DNS server : uses a specific DNS server for the query (default is the one set in Wndows)
-TestExchangeDomains (True/False): If True, all domains accepted by the Exchange Server are checked; the script must be executed by the Exchange Management Shell. The specification of -test domain cannot then be used.
The script can be downloaded here: