Could not reach the server
Symptom: "Could not reach … on port …. Check the address, the port, and any firewall between this server and it."
The SpamDuster server could not open a connection to your mail server.
- Check Host / IP and Port under Destination mail server in Advanced.
- Check that your mail server is running and listening on that port.
- Allow the SpamDuster server's IP address through every firewall in front of your mail server, on that port. To
find the IP address, look up your Mail host (MX target), for example
nslookup 123456.customer.spamduster.com. - Select Test without saving again.
The server will not relay for your domain
Symptom: "Reached …, but it will not relay for … — add this server's IP address to the list of hosts allowed to relay on your mail server."
Your mail server answered but does not accept mail for that domain from the SpamDuster server.
- Check that the domain is one your mail server hosts.
- On your mail server, add the SpamDuster server's IP address to the hosts it accepts or relays mail from.
- Test again.
The server refused the test address
Symptom: "… answered as a mail server, but refused postmaster@…. That address may simply not exist, so this is not conclusive."
The test guessed a postmaster@ address because none was given, and your server does not have it. This does not
mean anything is wrong. Enter a real mailbox in Test with address and test again.
The server deferred the test
Symptom: "Reached …, but it deferred …: … — a temporary refusal, worth retrying."
Your mail server answered with a temporary refusal, for example because it greylists new senders. Wait a few minutes and test again. If it keeps happening, add the SpamDuster server's IP address to your mail server's greylisting or rate-limit exceptions.
The server answered, but not as a mail server
Symptom: "… answered, but not as a mail server."
Something other than a mail server is listening at that address and port, for example a web server. Check the port:
most mail servers receive mail on port 25.
Still failing
Open a ticket with the full message the test showed. See Open a support ticket.