We are not using the ...

*MY* outbound mail server for our nagios system (it delivers it locally to the machine's SMTP Agent) does not do batch mode. It also does *not* send out 150 messages, using 150 connections at the same time to the same MX records. Its purposely setup to do them all serially.

Sure, I sometimes get a few hundred messages in 15 minutes. But every single one of them is sent ... singly and one at a time to the same MX record.

Now, if my nagios server needs to send out messages to a few AT&T recipients, a few Verizon recipients, a few T-Mobile recipients and a few Rogers recipients all at once, there will be multiple mail drops happening at the same time to each MX, but serially for those MX records.

I guess, I thought through this a bit more than others, as I am the recipient of some Denial of Service attacks... I didn't want to be a perp.

Many people don't test and just assume things are good.

I also, once I have an incident... I turn off notifications... until the event is past.

I guess I'm not the norm.

Post #333,473 by folkert 9/30/10 7:05:49 PM Reply	We are not using the ... direct to SMS delivery. We use the SMTP gateway, which is a "natural" throttle.
Post #333,489 by jake123 9/30/10 10:33:56 PM Reply	Yes, that is the part of the infrastructure that I run and it amounted to a DoS attack on it when a Canadian uni had a badly configured set of Nagios boxes run wild last week. Sure, it's a natural throttle, but when the mail server is throttling it, it's throttling everybody else using it as well.
Post #333,531 by folkert 10/1/10 10:43:23 AM Reply	I'm sorry... I should have said... MY outbound mail server for our nagios system (it delivers it locally to the machine's SMTP Agent) does not do batch mode. It also does not send out 150 messages, using 150 connections at the same time to the same MX records. Its purposely setup to do them all serially. Sure, I sometimes get a few hundred messages in 15 minutes. But every single one of them is sent ... singly and one at a time to the same MX record. Now, if my nagios server needs to send out messages to a few AT&T recipients, a few Verizon recipients, a few T-Mobile recipients and a few Rogers recipients all at once, there will be multiple mail drops happening at the same time to each MX, but serially for those MX records. I guess, I thought through this a bit more than others, as I am the recipient of some Denial of Service attacks... I didn't want to be a perp. Many people don't test and just assume things are good. I also, once I have an incident... I turn off notifications... until the event is past. I guess I'm not the norm.

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