iscmrtutprl14.isc.upenn.edu has no MX records.
Question and response
Question
dig iscmrtutprl14.isc.upenn.edu. MX
Answer
The response has no answer records.
Authority
upenn.edu. 600 SOA ipam1.nnn.upenn.edu. hostmaster.upenn.edu. 2002373567 10800 3600 604800 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0