Ihug still fighting to sort out spam fiasco
Hard-hit by an avalanche of incoming spam messages, ISP Ihug has decided to introduce further checks on servers wanting to send email to its customers. From now on, email servers must have matching reverse and forward pointing records in the Domain Name System (DNS) for messages to be accepted by Ihug's SMTP (Simple Mail Transfer Protocol) servers.
But this move to combat spam was criticised by at least one New Zealand network operator because Ihug's servers simply reject messages with any SMTP error codes to let the sending hosts know what is going on.
In doing so, the sending email servers are likely to continue trying to connect to Ihug's servers, which may increase the load on the latter. An Ihug network engineer agreed with the operator in question, saying dropping connections to mail servers without explanation is unhelpful to say the least
» Computerworld - Juha Saarinen - 20-11-2006