I set up a new firewall rule at work and it blocked our own email server

I was trying to tighten up our office network in Chicago by adding a rule to block all traffic from a specific country code. Turns out our email server routes through a data center there, so nobody got any external messages for half a day. I learned to always check where your own services are hosted before you block a whole region. Has anyone else had a rule backfire because they didn't map their own traffic first?

2 comments

2 Comments

terry_walker6d ago

Half a day" of blocked email sounds like a quiet morning. At least you found the problem before anyone noticed.

kim.charlie6d ago

Our support line got 47 calls about missing order confirmations in those four hours. Each one of those calls represents a real person who had their time wasted and started to doubt our service. Finding the problem quietly is not a win, it's just damage control for a failure that should not have happened in the first place. That's half a business day of broken trust we have to rebuild. Calling it a quiet morning really misses the impact on the customers who were trying to reach us.