Below is the list of SMTP Servers (hostnames and IP addresses):


Canada:

mx01.tor.mta.isheriff.com,162.248.221.204
mx02.tor.mta.isheriff.com,162.248.221.136

mx01.tor.mda.isheriff.com,162.248.221.135

mx02.tor.mda.isheriff.com,162.248.221.244


Germany:

mx01.de.mta.isheriff.com,88.198.65.211
mx02.de.mta.isheriff.com,88.198.65.187
mx01.de.mda.isheriff.com,5.9.32.200
mx02.de.mda.isheriff.com,176.9.73.130


South Africa:
mx01.za.mta.isheriff.com,129.232.187.90
mx02.za.mta.isheriff.com,129.232.187.98

mx01.za.mda.isheriff.com,129.232.187.122

mx02.za.mda.isheriff.com,129.232.187.130


United States of America:

mx01.dfw.mta.isheriff.com,209.177.156.120
mx02.dfw.mta.isheriff.com,192.73.248.15

mx01.dfw.mda.isheriff.com,209.177.156.29

mx02.dfw.mda.isheriff.com,209.177.156.60


Note: Port 25 should be open to the above mentioned servers to allow email flow.