Afrihost SMTP restrictions

+4 votes
Are there any restrictions on the Afrihost SMTP?
asked Oct 7, 2014 in ADSL by anonymous

1 Answer

0 votes

The short answer is: yes.

The following restrictions apply to smtp.afrihost.co.za when you send mail using SMTP:

  • Relaying is only allowed from the Afrihost DSL IP range. You cannot use smtp.afrihost.co.za from other providers (e.g. wireless).
  • You can only send to a maximum of 100 recipients per mail message. This includes To:, Cc: and Bcc:.
  • The size limitation is 102.4 Mega Bytes per message.
  • Every To: or Cc: address in the mail body must be valid
  • The sender and recipient domains must be a Fully Qualified Domain Name and must be a valid resolvable DNS domain.
  • The sender From: address cannot be free mail services, i.e. Yahoo, Hotmail, GMail, etc are not accepted.
  • If your ADSL line operates as an open relay, your access will be blocked.
  • Your e-mail address will be blacklisted if you send mail to a spamtrap
  • Your e-mail address may be blacklisted if an abuse complaint is received
  • No more than 50 recipients per minute, after which you will wait.
  • No more than 7 concurrent SMTP connections
  • No more than 50 attachments
  • Nothing that looks like malware mail is permitted
  • Nothing that looks like spam is permitted


If you send mail directly to another provider, you might be unable to send mail if one of the following happens:

  • A machine on your network has triggered the automatic bulk SMTP blocker. This applies to an IP that connects to over 30 machines' SMTP ports in 5 minutes. If this happens to you, run a sniffer like wireshark from http://wireshark.org to see if there is something happening that you don't know about.
  • If there is an unresolved SPAM complaint, Afrihost will have filtered your outgoing SMTP. If you resolve the problem, that's great, but do let us know that you would like us to remove the filtering. If you want to be sure that this never affects you, you can use a different port (submission 587/tcp is the official alternative).
  • You have an anti-virus or firewall program which is attempting to send to an incorrect SMTP server, and doesn't realise that the connection has changed.
  • There are more than a few paranoid anti-spam systems out there that panic because your ADSL IP address is listed as a spam source, even though you are sending via a relay! The blacklisting is (usually) due to the previous irresponsibility of someone to whom the IP was assigned. Sometimes this is you. When it's not, there is not much we can do about this, because all the mail you send will bear your IP address. The recipient should be able to handle the problem gracefully.


You can diagnose how far you can get with port 25/tcp using tcptraceroute (linux) or tcptrace from http://tracetcp.sourceforge.net/

answered Oct 8, 2014 by warmhands (470 points)
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