Firewall and Misc

Firewall is a set of rules to restrict ip, port, domain names, string etc. from public n/w.


Hardware + Software firewall in general

Host specific firewalls comes along with OS like Windows Firewall.



RDS's can't be accessed

1) Check security group inbound rules
2) DNS name using dig, nslookup, nc etc or digwebinterface.com
3) Memory on EC2 or ports, credentails etc.


We need private subnet and pvt subnets to save public ip's as those are limited and security concerns too.


pvt subnets-- route tables of pvt subnet to point to NAT instance hosted in the public subnet, where route tables of public subent mapped to internet gateway.