Hot answers tagged firewall
Don't bother. fail2ban maintains its own state and will recreate its firewall rules when restarted.
NLB operates at the Ethernet layer, which is below the whole TCP/IP stack and thus below any firewall. And, anyway, NLB hosts must be connected to the same network segment: there can't possibly be any block between them.
First off, verify that you can connect from your local machine... you can just telnet to port 443, both on localhost (127.0.0.1) as well as on your machine's IP address. You should at least get an answer (ie. verification that there is a listener on that port). Example - This is what you do not want: $ telnet 127.0.0.1 443 Trying 127.0.0.1... telnet: ...
is it possible to just allow the EC2 instance to access the S3? Is there any ip connected to the S3 bucket or can I set one? S3 uses many IPs. I suspect it would be difficult to nail down a list of them all. Additionally, there is no IP-to-bucket mapping, and it is not possible for you to specify an IP for a bucket. S3 is a managed service that AWS ...
NLB heartbeats operate at Layer 2, so no firewall ports need to be opened. Here's a screenshot of an NLB heartbeat, captured with Microsoft Network Monitor:
The shodanshok's comment is right: If you can't telnet the SMTP server, the connection is blocked at the gateway or server level. So I opened a ticket for Digital Ocean's support and got the following response: To curb a recent increase in abuse and SPAM, we have an initial SMTP block on new accounts created in certain contexts. To remove ...
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