Why are some emails being blocked?
Posted: 29 Mar 2024, 16:21
On March 22, I discovered that SOME emails to users on my server were being returned to senders. Some were definitely coming through, but some weren't. I ended up having to disable CSF, at which time hundreds of emails started to come in.
This problem didn't happen on March 21, so it was a new issue after I hadn't changed anything. So it had to be something automated.
These IPs were in my Temp Block:
64.145.93.198
50.223.38.94
72.177.80.230
And this is the only one in my Perm Block:
50.223.176.171
But IPs that were definitely blocked were (based on the ones that came in to me after I disabled CSF):
170.10.151.103
170.10.150.241
198.2.144.27
149.72.208.120
168.245.59.112
167.89.89.106
You can see that none of the delayed emails have IPs in the same range as those blocked.
It's also notable that I use Cloudflare, and I THINK that I have it configured properly with CSF. But I hadn't changed anything with Cloudflare recently either, and disabling CSF is what seemed to "fix" the problem.
Any suggestions on what could have been blocking the emails?
This problem didn't happen on March 21, so it was a new issue after I hadn't changed anything. So it had to be something automated.
These IPs were in my Temp Block:
64.145.93.198
50.223.38.94
72.177.80.230
And this is the only one in my Perm Block:
50.223.176.171
But IPs that were definitely blocked were (based on the ones that came in to me after I disabled CSF):
170.10.151.103
170.10.150.241
198.2.144.27
149.72.208.120
168.245.59.112
167.89.89.106
You can see that none of the delayed emails have IPs in the same range as those blocked.
It's also notable that I use Cloudflare, and I THINK that I have it configured properly with CSF. But I hadn't changed anything with Cloudflare recently either, and disabling CSF is what seemed to "fix" the problem.
Any suggestions on what could have been blocking the emails?