I've had a problem with one of my SBS clients. A staff member sent out an email to 300+ recipients with a 2.1Mb attachment. They only have an ADSL2 internet connection and all ____ broke loose. It took hours to fully go and their internet service was significantly degraded whilst it was all happenning. Several hours after the email was "sent" I tried to logon remotely (using the same internet connection) and after much waiting/timing out etc. I eventually managed to get onto their server. Looking at the exchange queues there were by then about 20+ emails "Active" and another 30+ emails waiting for a retry. So it was eventually getting through them. Slow but it was happenning. But when I looked at the Exchange settings it had a default value of 1000 Maximum Concurrent Outgoing connections and 20 for each domain. This number seems ridiculously large to me. Surely I wouldn't want an SBS server attempting to connect to more than a few other mail servers concurrently? I'm guessing that what happened was as soon as the email hit Exchange it tried to connect to multiple other mail servers at once and attempted delivery of the large'ish email. Due to the multiple concurrents, any one delivery would have been quite slow. There would have been timeouts, retries, everything happening. Chaos and a max'ed out internet connection. I have since changed the maximum concurrent outgoing connections to 5. (I hate changing defaults......I always expect that they are set at a value for a good reason) My questions are: 1.....am i right in what I think was probably happening? 2.....will my change of the default value to 5 cause me any unforeseen consequences? 3.....Is there a better way to do this? Thanks in advance PHerbie Australia

On Mon, 7 Jun 2010 00:34:08 +0000, PHerbison wrote: [ snip ] >But when I looked at the Exchange settings it had a default value of 1000 Maximum Concurrent Outgoing connections and 20 for each domain. This number seems ridiculously large to me. Surely I wouldn't want an SBS server attempting to connect to more than a few other mail servers concurrently? Don't confuse the ability of Exchange to send e-mail in large quatities with the inadequate bandwidth of the connection used to send the e-mail. Use a bigger pipe and SBS will do just fine. >I'm >guessing that what happened was as soon as the email hit Exchange it tried to connect to multiple other mail servers at once and attempted delivery of the large'ish email. Due to the multiple concurrents, any one delivery would have been quite slow. There would have been timeouts, retries, everything happening. Chaos and a max'ed out internet connection. I have since changed the maximum concurrent outgoing connections to 5. (I hate changing defaults......I always expect that they are set at a value for a good reason) My questions are: 1.....am i right in what I think was probably happening? Only if your thinking was related to the inadequate connection. >2.....will my change of the default value to 5 cause me any unforeseen consequences? That depends alot on the SMTP traffic patterns. If you send lots of "normal" size e-mail to many different domains you may be throttling your connections back too far. >3.....Is there a better way to do this? A bigger pipe? Some user training? Restrict the maximum size of e-mail? --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP