10th January 2021

Outbound Filters SBL'd IP in headers

One of our outbound filters had been listed at Spamhaus for reasons unrelated to our service. The IP belongs to a service provider, our filters are split between two service providers. While that IP does not send mail, it is recorded in headers and some software (SpamAssassin being one) may check the reputation of all IPs in the headers, which could lead to increased spam folder delivery. The server in question was pulled from rotation pending resolution.