Protip: if you’re getting Nagios alerts on an iPhone, and you have your contact set as: firstname.lastname@example.org, you’ll get messages from a ‘sender’ that looks like: “1 (410) 000-173″. This is not someone in Maryland, it’s a special address so that AT&T can route a reply back to the sender if need be.
The side affect of this is when/if you get a boatload of alerts (which can happen in cascading failure scenarios where you don’t have any Nagios dependencies or event handlers set up) you’re gonna have to spend a proportional boatload of time swiping and deleting those alerts one by one.
This, of course, is a major bummer.
A solution is to set your contact info in nagios instead to email@example.com, which will properly set a “from” address on your iPhone, so when it comes time to delete the boatload of messages, you can do it in a single ‘delete conversation’ swipe.
Caveat: If you do this (set to mms.att.net, instead of txt.att.net) you’ll lose the ability to reply to a Nagios alert. This presumably will affect those smart folks who have set up the ability to acknowledge an alert from their phone via a reply/procmail mechanism.
Bonus protip: make it so that you don’t ever get boatloads of Nagios alerts at once. That will help, too.