I agree. There doesn't seem to be a way to limit recipients/second. That would be useful. At 10:57 AM -0400 5/1/08, Valdis Kletnieks wrote about Re: Experience with Rate Limits: >On Thu, 01 May 2008 07:22:49 EDT, Bill Verity said: > >> VMS: SMTP_RATE_LIMIT "12Mbps" >> unix: SMTP_RATE_LIMIT="12Mbps" >> export SMTP_RATE_LIMIT >> Win:SMTP_RATE_LIMIT=12Mbps > >Unfortunately, unless your actual upstream network connection is congested >(in which case you probably have a bigger problem), limiting the bandwidth >usually doesn't impact performance anywhere near as much as limiting the >number of recipients/second (especially if you have a large mailing list >sent to a lot of sites) - the TCP 3-packet handshakes and the first few SMTP >round/trips (EHLO/MAIL FROM/RCPT TO) end up dominating the network traffic, >especially if the remote site doesn't advertise the ESMTP PIPELINING extension. > >Phrased differently - a 4K E-mail to 5,000 users usually ends up "costing" almost >the same as a 40K E-mail to 5,000 users, and 4K to 5,000 users "costs" a lot >more than 40K to 500 users... -- Good friends are hard to find, harder to leave, and impossible to forget. Bill Verity - 814-865-4758 Fax: 814-863-7049 215A Computer Building - Information Technology Services, Penn State University At the office - on my Mac, of course ;-)