You can check the DNS with whatismydns.net and intodns.com. Source: about 1 year ago

Feel free to check https://intodns.com/ and https://www.whatsmydns.net/ to monitor propagation and ensure the DNS records are correctly set. Source: about 1 year ago

Just in case, it would be a good idea to check the DNS with a tool like intodns.com, just to make sure everything is working as intended. Source: over 1 year ago

I know this is a little old but I came across some of my tools I used when going through bookmarks: - https://mail-tester.com Although I already mentioned this above, this has been a lifesaver when it comes to figuring out why 3rd parties are rejecting your mail - https://intodns.com Helps give you a more thorough view into how your DNS settings are configured. - https://mailu.io Not a diagnostic tool, but a... Source: over 1 year ago

If you need external confirmation of things, intodns.com and dnschecker.org are both pretty good. Source: over 1 year ago

If you have a BGP peering with you ISP/upstream provider, ask them if they have a blackhole community you can broadcast to. Usually they are ASN:666. The only downside is you would only be able to advertise your IP address to that, essentially killing your internet (if that's your only IP) as long as the block is up. We usually set our filter to 15 minutes and most attackers give up after that. At this level, you... Source: about 1 year ago

Have you looked at fastnetmon ? It's freemium and It looks like the commercial version would work you, but I think the community edition is aslo worth a look. It's primary function is to detect DDOS attacks, but it can export data in ways that might be useful to you. Source: about 2 years ago

To mitigate DoS attacks means you need information - preferably before the users start screaming. Running sampling on your edge router with something like Fastnetmon will give you alerting of a probable DDoS attack before it becomes a significant problem. Source: almost 3 years ago