Testing a Connection

On Client1 (10.0.1.11)

Confirm that the problem exists by curling the headers of 10.0.1.10 from 10.0.1.11:

curl -I 10.0.1.10

On Server1 (10.0.1.10):

Verify a service is listening on port 80:

ss -lntp | grep :80

If nothing is listening, check if Apache is running:

systemctl status httpd

Start Apache if necessary:

systemctl start httpd

Did that resolve the problem?

On Server1 (10.0.1.10):

Verify that the firewall is configured to permit http traffic:

firewall-cmd --list-services

If http isn't present, it will need to be added:

firewall-cmd --permanent --add-service=http

And the firewall rules will need to be reloaded to take effect:

firewall-cmd --reload

Verify that the problem is resolved.

On Server1 (10.0.1.10):

You will need to open port 443 in the firewall. You can do it with:

# firewall-cmd --permanent --add-service=https

And then reloading the firewall config with this:

# firewall-cmd --reload

You will need to facilitate listening on port 443 from Server1 (10.0.1.10). You can do this by installing the nmap-ncat package for CentOS:

# yum install nmap-ncat

And then using it to listen on port 443:

# nc -l -p 443

On Client1 (10.0.1.11):

Install telnet:

$ yum install -y telnet

You can verify that 443 is accessible by using telnet:

$ telnet 10.0.1.10 443