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Testing a Connection

In this hands-on lab, you will need to troubleshoot connectivity issues between `Client1` ( and `Server1` ( You will need to determine why the website at is unreachable, and prep the host to make sure connectivity is in place to permit SSL traffic once it's configured.

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Path Info

Clock icon Intermediate
Clock icon 1h 0m
Clock icon Nov 14, 2018

Contact sales

By filling out this form and clicking submit, you acknowledge our privacy policy.

Table of Contents

  1. Challenge

    Confirm the problem.

    On Client1 (

    Confirm that the problem exists by curling the headers of from

    curl -I

  2. Challenge

    Confirm, and maybe resolve, Apache's status.

    On Server1 (

    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?

  3. Challenge

    Check firewall rules.

    On Server1 (

    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.

  4. Challenge

    Permit https traffic in the firewall and verify.

    On Server1 (

    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 ( 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 (

    Install telnet:

    $ yum install -y telnet

    You can verify that 443 is accessible by using telnet:

    $ telnet 443

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