When a single user initiates a 'bulk' mailout (bulk can be as few as 20 emails or as many as 3,000) to multiple recipients, the entire local area network (which only has 50 users) becomes unusable, the response drops to basically zero until 90% of the emails have been delivered. I've tried 'freezing' all the emails with the intention to then unfreeze/release the emails after hours, but it doesn't seem to make any difference. Any ideas??

Exchange is a poor bulk emailing tool, so if you are doing regular bulk email runs then I would suggest that you look at a bulk emailing application or even outsourcing it. When Exchange sends an email it will use all of the bandwidth that is available to send those messages, which is how it is designed, and why it is a poor bulk emailer. However unless you have everything going through the Exchange server, or a poor design somewhere else (like a hub rather than a switch) the traffic from Exchange shouldn't stop LAN traffic. It would tend to indicate a problem elsewhere in the network which is only shown when Exchange uses all of the bandwidth for its use. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Exchange doesn’t offer traffic control function. You can control network traffic by switch and router. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Yes, I was already heading down that path - I'd installed some bulk mailout software but it was still directed through the exchange server. I've now created a windows live email account and intend to direct the mailout through smtp.live.com, bypassing our exchange server. But...in the meantime...this morning a user sent a 7.5 mb email copied to 15 users and our lan and internet died. I stopped the Exchange Information Store service and the network came back to life. I re-started the Information store and the network died so as a matter of interest I unplugged the Exchange server from the switch - it took about 10 minutes for the network to return to 100% performance. I then tried stopping the Information Store while the server was disconnected but the service wouldn't stop - the service will only stop when the server is connected to the switch/LAN????? Any ideas?? Oh yes, also currently the Exchange service is affecting LAN/Internet performance even when the queue shows no emails being delivered... Also, I deleted the 15 emails from the queue but they keep re-appearing and trying to re-send - they just appear as if by magic in the queue again - I delete them again and, half an hour later, they re-appear...???? David

The behaviour you have seen with the network cable disconnected doesn't surprise me. Exchange is very dependant on Active Directory and when you shutdown Exchange (Which is effectively what you are doing by stopping the information store) it needs to talk to the domain. With the network cable disconnected it cannot do that, so you have to wait for the service shutdown timeout to occur. I don't think Microsoft are going to take very kindly to you sending bulk email messages through their SMTP service. If you have bulk email software in place, then why aren't you sending that straight to the Internet? That is how they are designed to be used. Ideally have multiple IP addresses and then have the bulk email application use its own IP address. They can usually also cope with bounces and rejects. I would suggest that you start by running the Exchange Best Practises analyser against the system and ensure that it has the latest network card drivers. This may not be an Exchange issue, it could well be a faulty NIC, something like that. Unless you have an Internet connection that allows the full bandwidth of the network card to be used, even a large email send shouldn't flood the LAN, because the Internet connection cannot shift the packets quick enough. My instinct is that this is something outside of Exchange. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Thanks for the extra info - it shows my lack of Windows server knowledge :) I'm not sure that the Mailing software we have has it's own emailing capability, it seems to rely on using an external SMTP service...I'll have a closer look and/or look for alternate mailing software. Exchange Best Practices sounds like a great idea - I'll give it a go. Further information: I was fossicking around in the depths of Exchange and fell across the SMTP virtual server and discovered that one of my offsiders who had been experimenting with the SmartHost functionality had left a test smarthost sever setting active. Do you think this may have contributed to the original problem?? eg if Exchange was sending out continual packet retries trying to find the non-existent smarthost?? or something like that... David

You need to delete the temp table, it's a common symptom when you do a blast mail like that, messages are still in the temp table and when you restart IS those messages will start to process again. The instructions in my blog below are for Ex 2003, should be the same for 2007 but haven't tested since I haven't run across an issue since then to have to delete the temp table. Using MFCMAPI To Delete Exchange Temp Table http://msexchangetips.blogspot.com/2006/08/using-mfcmapi-to-delete-exchange-temp.htmlJames Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Where was the smart host set? On the SMTP virtual server? If so, then all of your email has been going through that. Remove it. If the bulk emailing software needs another SMTP server to run, then get some different bulk emailing software. That is like having a car without an engine (so that is a caravan?). The main reason for recommending the use of a third party bulk email software is because it can manage the mail flow, including bundling messages up to the same ISP etc, and reduce the bandwidth use. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Thanks James - I'll have a look tomorrow. David

Hi Can you update your process?Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Sorry, no progress yet - It's a five day per fortnight support job and I was sick as a dog since Thursday night and didn't go into work on Friday and won't be back in until this Thursday to try anything - will update on Thursday. Thanks for all the help and your patience. Cheers David

Hi James, I've downloaded mfcmapi - I'll try it out tonight. Thanks David

Simon, Thanks - have run Best Practices Analyser and fortunately (or not..??) it didn't highlight many issues - maybe virtual memory, move temp directory to non-system disk, drivers more than 2 years old. Have downloaded an updated nic driver and will install this evening. David

Updated nic driver didn't appear to influence proceedings at all... All network traffic slows to a snail's pace when multiple emails are sent at the same time. In the meantime...looking for a workaround...we had a 'spare' internet line with an alternate isp so I've configured the gateway on all network PC's to use the alternate internet connection and left the exchange server using the original internet connection. Then, reverting to normal outlook based email (instead of bulk email software), sending 200 emails simultaneously seems to have minimal impact on the network, and, apart from a slight slowdown when the 200 emails are initially processed by the exchange server, minimal impact on internet performance as well. This is a convenient workaround, but doesn't provide an answer to the original issue of email traffic killing the network. Hmmmm...more thinking required...