RedIRIS considered one of the most effective and economic to reduce spam is to block email traffic originating from certain suspicious IP addresses, which are included in Reputation lists, updated in real time.
RedIRIS places the IRISRBL (Reputation Based/Block List) reputation service at the disposal of its affiliated institutions; this service uses the sender's IP to identify spam e-mail in order to immediately block and delete it.
The service aggregates the IP addresses identified as malicious due to their bad reputation in such a way that a simple DNS query is all it takes to get information on whether to accept the e-mail or not. The service also detects and deletes “false positives” (IP addresses that are mistakenly treated as spam and stored as malicious IPs) and adds them to the “RedIRIS White List”. This White List includes the trusted IP addresses of all the e-mail servers of Spanish Internet providers, grouped in the ABUSES Forum, which RedIRIS co-ordinates.