# Iptables

### Delete current rules and chains

```bash
iptables --flush
iptables --delete-chain
```

### Allow loopback

```bash
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
```

### Drop ICMP

```bash
iptables -A INPUT -p icmp -m icmp --icmp-type any -j DROP
iptables -A OUTPUT -p icmp -j DROP
```

### Allow SSH, HTTP, DNS

```bash
#SSH
iptables -A INPUT -s 10.10.10.10/24 -p tcp -m tcp --dport 22 -j ACCEPT

#HTTP/HTTPs
iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
iptables -A INPUT -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT

#DNS
iptables -A INPUT -p udp -m udp --sport 53 -j ACCEPT
iptables -A INPUT -p tcp -m tcp --sport 53 -j ACCEPT
iptables -A OUTPUT -p udp -m udp --dport 53 -j ACCEPT
iptables -A OUTPUT -p tcp -m tcp --dport 53 -j ACCEPT
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://www.pwny.cc/so/linux/iptables.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.