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Packet Filter Rule - Exercise Result

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Configure Network Firewall

Your packet filter rules should look like this:
Packet Filter Rules
Packet Filter Rules
  1. Rule number one allows HTTP from your internal network to the outside world so that your users are able to browse the Web.
  2. Rule number two allows SSL from your internal network to the outside world so that your users are able to make online purchases.
  3. Rule numbers three and four allow FTP traffic so that your users can request and download information from the Web.
  4. Rule number five allows SMTP traffic into your mail server only.
  5. Rule number six allows the outside world to access your internal Web server.
  6. Rule number seven denies all other incoming IP traffic.


Here is the transcription of the table from the image: 
| Rule # | Action | Source Address  | Destination Addr | Port     | Protocol | Path 
|--------  |--------|------------------------|----------------------|--------- |-------------|-------------|
| 1         | Allow  | 192.168.0.0/24     | *                           | 80              | HTTP | Out         |
| 2         | Allow  | 192.168.0.0/24     | *                           | 443            | SSL    | Out         |
| 3         | Allow  | 192.168.0.0/24     | *                           | 21              | FTP    | Out         |
| 4         | Allow  | *                             | 192.168.0.0/24   | 20 > 1023 | FTP-Data | In      |
| 5         | Allow  | *                             | 192.168.0.10      | 25              | SMTP       | In      |
| 6         | The machine if you tell |    | 192.168.0.20      | 80              | HTTP       | In      |
| 7         | Block  | *                            | 192.168.0.0/24   | *                  | IP              | |

Conclusions:
  1. Outgoing Traffic: - Rules 1 to 3 allow outbound traffic from the `192.168.0.0/24` network to any destination (`*`):
    • HTTP traffic on port 80.
    • SSL traffic on port 443.
    • FTP traffic on port 21.
  2. Incoming Traffic:
    • Rule 4 allows incoming FTP-Data traffic on ports 20 to >1023 from any source to the `192.168.0.0/24` network.
    • Rule 5 allows incoming SMTP traffic on port 25 from any source to `192.168.0.10`.
    • Rule 6 allows incoming HTTP traffic on port 80 from any source to `192.168.0.20`.
  3. Blocking Rule:
    • Rule 7 blocks all incoming IP traffic (`*`) to the `192.168.0.0/24` network. This rule is placed last, meaning it will block any incoming traffic that is not explicitly allowed by previous rules.

Key Takeaway:
  • The rules are set up to allow specific outbound traffic (HTTP, SSL, FTP) from the `192.168.0.0/24` network and to allow specific inbound traffic (FTP-Data, SMTP, HTTP) to designated IPs within the `192.168.0.0/24` network.
  • The final rule (Rule 7) acts as a catch-all to block any other inbound traffic not explicitly allowed by the preceding rules. This is a common security practice to ensure that only the desired traffic is permitted while everything else is blocked.