RBL and URIBL's with very high average response times
Question asked by Mark Thornton - 3/27/2023 at 2:37 PM
I have noticed some of the RBL's and URIBL's have high and very high average response times. For example, McAfee cidr.bl.mcafee.com is showing 21671 seconds. SURBL multi.surbl.org is 32412 seconds. Should I remove these from the spool and inbound smtp filtering? What should I expect as values for these sites? Is there a max amount of time SmarterMail will keep waiting on an RBL to respond?

2 Replies

Reply to Thread
Employee Replied
Employee Post Marked As Answer
Hi Mark, 

In the upcoming major release, we've made some great improvements for RBL/URIBL handling. In the current public build, I do believe there is a timeout in place. But it cycles through each RBL/URIBL one at a time. In the upcoming release, we shotgun the RBL/URIBL requests all at once and take the responses after 5-10 seconds, effectively implementing a timeout for all at one time. 

21671 and 32412 milliseconds are indeed fairly high response times. Ideally, you want to stay under a second (1000 ms), especially for any RBLs that are doing Inbound SMTP blocks, since the SMTP session is so time-sensitive. For these two RBLs, I think it would be alright to remove them from spool and inbound SMTP filtering. McAfee has been removed as a default RBL in the next release, and we don't use SURBL in-house either. 
Mark Thornton Replied
Thank you. I am looking forward to the new version.

Reply to Thread