iptable doc
This commit is contained in:
@@ -1,52 +1,258 @@
|
||||
## First Whitelist Port and Block Ports at the End
|
||||
# 🛡️ Iptables & Netfilter Guide
|
||||
|
||||
|
||||
## 🌐 Overview
|
||||
|
||||
```bash
|
||||
iptables -A/-I/-D INPUT/OUTPUT/FORWARD -i/-o interface -s/-d address -p tcp/udp/icmp --sport/--dport 80 -j ACCEPT/REJECT/DROP/LOG/MASQUARATE
|
||||
**iptables** works with **Netfilter** to manage and control network traffic on Linux systems.
|
||||
|
||||
---
|
||||
|
||||
## 🔗 Connection Types
|
||||
|
||||
1. **NEW** – A new connection being initiated
|
||||
2. **ESTABLISHED** – An existing, ongoing connection
|
||||
3. **RELATED** – A new connection related to an existing one
|
||||
|
||||
---
|
||||
|
||||
## 🧰 iptables-persistent
|
||||
|
||||
Install iptables and save the rules to a file for persistence across reboots.
|
||||
|
||||
---
|
||||
|
||||
## 📂 Default Path
|
||||
|
||||
```plaintext
|
||||
/etc/iptables
|
||||
```
|
||||
|
||||
- `-A`: Append
|
||||
- `-I`: Insert
|
||||
- `-D`: Delete
|
||||
- `-i`: Input interface
|
||||
- `-o`: Output interface
|
||||
- `-s`: Source
|
||||
- `-d`: Destination
|
||||
- `-p`: Protocol
|
||||
- `--sport`: Source port
|
||||
- `--dport`: Destination port
|
||||
- `-j`: Action
|
||||
- `ACCEPT`: Accept the packet
|
||||
- `REJECT`: Reject the packet with an appropriate ICMP message
|
||||
- `DROP`: Silently discard the packet
|
||||
- `LOG`: Log the packet
|
||||
- `MASQUERADE`: Source NAT
|
||||
---
|
||||
|
||||
### Examples:
|
||||
|
||||
- `iptables -nvL`: Print Iptables Rules
|
||||
- `iptables -P INPUT DROP`: Drop All Incoming Packets
|
||||
- `iptables -P OUTPUT DROP`: Drop All Outgoing Packets
|
||||
- `iptables -A INPUT -p tcp --dport 22 -j ACCEPT`: Accept Incoming Traffic to Port 22 with TCP Protocol
|
||||
- `iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT`: Accept Outgoing Traffic from Port 22 with TCP Protocol
|
||||
- `iptables -A INPUT -p tcp -s 192.168.1.100 -j DROP`: Drop All Packets Incoming With TCP Protocol From 192.168.1.100
|
||||
- `iptables -A INPUT -p tcp --dport 443 -j ACCEPT`: Accept Incoming Traffic to Port 443 (HTTPS) with TCP Protocol
|
||||
- `iptables -A INPUT -p tcp -m multiport --dport 22,443,80,3306 -j ACCEPT`: Accept Incoming Traffic to Multiple Ports: 22 (SSH), 80 (HTTP), 3306 (Database), 443 (HTTPS) with TCP Protocol
|
||||
- `iptables -A INPUT -p tcp -m multiport --dport 22,443,80,3306 -d 192.168.10.0/24 -j ACCEPT`: Accept Incoming Traffic to Multiple Ports: 22 (SSH), 80 (HTTP), 3306 (Database), 443 (HTTPS) with TCP Protocol to Destination 192.168.10.0
|
||||
- `iptables -A INPUT -p tcp --dport 80 -m limit --limit 100/minute --limit-burst 200 -j ACCEPT`: Allow incoming TCP traffic on port 80 with rate limiting
|
||||
- `iptables -t NAT -A PREROUTING -i ens33 -p tcp --dport 80 -j REDIRECT --to-port 443`: Redirect traffic from port 80 to port 443 using NAT
|
||||
|
||||
### Saving rules for permanent:
|
||||
|
||||
To save the rules for permanent usage, you can install the `iptables-persistent` package:
|
||||
## ⚙️ Command Format
|
||||
|
||||
```bash
|
||||
apt install iptables-persistent
|
||||
iptables -t <table-name> <option> <chain-name> <match> -j <action>
|
||||
```
|
||||
|
||||
Then, save the rules to the appropriate file:
|
||||
---
|
||||
|
||||
## 🏷️ Table Names
|
||||
|
||||
| Table Name | Purpose |
|
||||
| ---------- | -------------------------------- |
|
||||
| filter | Default – Filtering Packets |
|
||||
| nat | Network Address Translation |
|
||||
| mangle | Packet alteration/editing |
|
||||
| raw | Pre-processing packets before OS |
|
||||
|
||||
---
|
||||
|
||||
## 🔄 Chains
|
||||
|
||||
| Table | Chains |
|
||||
| ------ | ----------------------------------------------- |
|
||||
| filter | INPUT, OUTPUT, FORWARD |
|
||||
| nat | PREROUTING, OUTPUT, POSTROUTING |
|
||||
| mangle | PREROUTING, INPUT, FORWARD, OUTPUT, POSTROUTING |
|
||||
| raw | PREROUTING, OUTPUT |
|
||||
|
||||
---
|
||||
|
||||
## 🚦 Chain Functions
|
||||
|
||||
| Chain | Description |
|
||||
| ----------- | -------------------------------------------------------- |
|
||||
| INPUT | Incoming connections to the server |
|
||||
| OUTPUT | Outgoing packets from the server |
|
||||
| FORWARD | Packets routed through the server to other destinations |
|
||||
| PREROUTING | Edit packets before routing |
|
||||
| POSTROUTING | Edit packets after routing and before exiting the server |
|
||||
|
||||
---
|
||||
|
||||
## 🔧 Options
|
||||
|
||||
| Option | Meaning |
|
||||
| ------ | ----------- |
|
||||
| `-A` | Append rule |
|
||||
| `-I` | Insert rule |
|
||||
| `-D` | Delete rule |
|
||||
|
||||
---
|
||||
|
||||
## 🎯 Actions
|
||||
|
||||
| Action | Description |
|
||||
| ---------- | -------------------------------------------- |
|
||||
| ACCEPT | Accept the packet |
|
||||
| DROP | Drop the packet silently (no response) |
|
||||
| REJECT | Drop the packet and send a rejection message |
|
||||
| LOG | Log the packet details |
|
||||
| MASQUERADE | Perform NAT masquerading |
|
||||
|
||||
---
|
||||
|
||||
## 🧩 iptables Command Examples & Explanations
|
||||
|
||||
---
|
||||
|
||||
### 1️⃣ Save Current Rules to a File
|
||||
|
||||
```bash
|
||||
iptables-save > /etc/iptables/rule.v4
|
||||
iptables-save >> <file_path>
|
||||
```
|
||||
|
||||
💾 **Explanation:**
|
||||
This command saves the current iptables rules to a file (`<file_path>`). Useful for backing up or persisting your firewall rules.
|
||||
|
||||
---
|
||||
|
||||
### 2️⃣ List Rules in Default Filter Table
|
||||
|
||||
```bash
|
||||
iptables -nL
|
||||
```
|
||||
|
||||
📜 **Explanation:**
|
||||
Lists all rules in the default `filter` table, showing rules without resolving IPs to names (`-n` speeds it up).
|
||||
|
||||
---
|
||||
|
||||
### 3️⃣ List Rules in NAT Table
|
||||
|
||||
```bash
|
||||
iptables -t nat -nL
|
||||
```
|
||||
|
||||
🔄 **Explanation:**
|
||||
Lists all NAT table rules. NAT is used for modifying packets, like translating IP addresses.
|
||||
|
||||
---
|
||||
|
||||
### 4️⃣ Allow Traffic from a Specific IP (Insert Rule)
|
||||
|
||||
```bash
|
||||
iptables -t filter -I INPUT -s 192.168.1.100 -j ACCEPT
|
||||
```
|
||||
|
||||
✅ **Explanation:**
|
||||
Inserts (`-I`) a rule at the top of the `INPUT` chain to ACCEPT all packets coming from IP `192.168.1.100`.
|
||||
|
||||
---
|
||||
|
||||
### 5️⃣ Drop All Incoming Packets (Insert Rule)
|
||||
|
||||
```bash
|
||||
iptables -t filter -I INPUT -j DROP
|
||||
```
|
||||
|
||||
⛔ **Explanation:**
|
||||
Inserts a rule to DROP all incoming packets on the `INPUT` chain, effectively blocking all new inbound traffic.
|
||||
|
||||
---
|
||||
|
||||
### 6️⃣ Append Drop Rule at End of INPUT Chain
|
||||
|
||||
```bash
|
||||
iptables -t filter -A INPUT -j DROP
|
||||
```
|
||||
|
||||
⏳ **Explanation:**
|
||||
Appends (`-A`) a rule at the end of the `INPUT` chain to drop packets that don’t match previous ACCEPT rules.
|
||||
|
||||
---
|
||||
|
||||
### 7️⃣ Allow Incoming TCP Traffic on Port 22 (SSH)
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
|
||||
```
|
||||
|
||||
🔓 **Explanation:**
|
||||
Allows incoming TCP traffic on port 22, which is commonly used for SSH connections.
|
||||
|
||||
---
|
||||
|
||||
### 8️⃣ Drop Incoming TCP Traffic on Port 22 (SSH)
|
||||
|
||||
```bash
|
||||
iptables -I INPUT -p tcp --dport 22 -j DROP
|
||||
```
|
||||
|
||||
🚫 **Explanation:**
|
||||
Inserts a rule to DROP all incoming TCP traffic destined for port 22, blocking SSH access.
|
||||
|
||||
---
|
||||
|
||||
### 9️⃣ Drop TCP Traffic From a Specific IP
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp -s 192.168.1.100 -j DROP
|
||||
```
|
||||
|
||||
📵 **Explanation:**
|
||||
Drops all incoming TCP packets coming from IP `192.168.1.100`.
|
||||
|
||||
---
|
||||
|
||||
### 🔟 Allow Incoming TCP Traffic on Port 443 (HTTPS)
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
|
||||
```
|
||||
|
||||
🔐 **Explanation:**
|
||||
Allows incoming TCP traffic on port 443, used for secure HTTPS connections.
|
||||
|
||||
---
|
||||
|
||||
### 1️⃣1️⃣ Allow Multiple Ports Using Multiport Module
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp -m multiport --dports 22,443,80,3306 -j ACCEPT
|
||||
```
|
||||
|
||||
🎯 **Explanation:**
|
||||
Accepts incoming TCP traffic on multiple ports at once: SSH (22), HTTPS (443), HTTP (80), and MySQL (3306).
|
||||
|
||||
---
|
||||
|
||||
### 1️⃣2️⃣ Allow Multiple Ports From a Specific Subnet
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp -m multiport --dports 22,443,80,3306 -s 192.168.10.0/24 -j ACCEPT
|
||||
```
|
||||
|
||||
🏠 **Explanation:**
|
||||
Allows TCP traffic on ports 22, 443, 80, and 3306 but only if it originates from the subnet `192.168.10.0/24`.
|
||||
|
||||
---
|
||||
|
||||
### 1️⃣3️⃣ Limit Incoming Connections on Port 80
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 80 -m limit --limit 100/minute --limit-burst 200 -j ACCEPT
|
||||
```
|
||||
|
||||
🚦 **Explanation:**
|
||||
Limits HTTP (port 80) incoming connections to 100 per minute with a burst of 200, helping prevent DoS attacks.
|
||||
|
||||
---
|
||||
|
||||
### 1️⃣4️⃣ Redirect HTTP Traffic to HTTPS on Interface `ens33`
|
||||
|
||||
```bash
|
||||
iptables -t nat -A PREROUTING -i ens33 -p tcp --dport 80 -j REDIRECT --to-port 443
|
||||
```
|
||||
|
||||
🔄 **Explanation:**
|
||||
In the `nat` table's PREROUTING chain, this redirects all HTTP traffic (port 80) arriving on interface `ens33` to HTTPS port 443.
|
||||
|
||||
## 🎉 Summary
|
||||
|
||||
* **iptables** is a powerful Linux firewall tool
|
||||
* Works by managing **tables**, **chains**, and **rules**
|
||||
* Supports filtering, NAT, packet mangling, and raw processing
|
||||
* Persistence through `iptables-persistent` package
|
||||
* Flexible commands for network security and traffic control
|
||||
|
||||
114
Security & Networking/Iptables/temp.md
Normal file
114
Security & Networking/Iptables/temp.md
Normal file
@@ -0,0 +1,114 @@
|
||||
iptable work with net filter
|
||||
|
||||
connection type:
|
||||
1. new
|
||||
2. stablished
|
||||
3. Related
|
||||
|
||||
iptable-persitant --> install iptables and save in iptables file
|
||||
|
||||
|
||||
defualt path --> /etc/iptables
|
||||
|
||||
command format
|
||||
|
||||
```bash
|
||||
iptables -t <table-names> <option> <chain-name> <match> -j <action>
|
||||
```
|
||||
table name:
|
||||
1. filter (default) --> Filtering Packets
|
||||
2. nat --> Nating Service
|
||||
3. mangel --> Edit Packets
|
||||
4. raw --> edit packets before prossecc by os
|
||||
|
||||
chains:
|
||||
|
||||
1. filter:
|
||||
1. INPUT
|
||||
2. OUTPUT
|
||||
3. Forward
|
||||
2. nat
|
||||
1. OUTPUT
|
||||
2. PREROUTING
|
||||
3. PASTROUTING
|
||||
3. mangle
|
||||
1. INPUT
|
||||
2. OUTPUT
|
||||
3. Forward
|
||||
4. PREROUTING
|
||||
5. PASTROUTING
|
||||
4. raw
|
||||
1. OUTPUT
|
||||
2. PREROUTIUNG
|
||||
|
||||
INPUT : Connection Incomming into Server
|
||||
OUTPUT : Packets Outgoiing From server
|
||||
FORWARD : Packer incomming to server but the target is not server (routing)
|
||||
PREROUTING : EDIT Packets Before Routing
|
||||
PASTROUTING : Edit Packet After Routing And Before Exit From Server
|
||||
|
||||
option:
|
||||
1. `-A`: Append
|
||||
2. `-I`: Insert
|
||||
3. `-D`: Delete
|
||||
|
||||
actions:
|
||||
ACCEPT: accept the packet
|
||||
DROP: drop the packer without any msg
|
||||
REJECT: drop the packet with send message to packet sender
|
||||
LOG: Log The Packet
|
||||
MASQUERADE: Nating
|
||||
|
||||
```bash
|
||||
iptables-save >> <file_dir>
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -nL
|
||||
```
|
||||
```bash
|
||||
iptables -t nat -nL
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -t filter -I INPUT -s 192.168.1.100 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -t filter -I INPUT -j DROP
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -t filter -A INPUT -j DROP
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -I INPUT -p tcp --dport 22 -j DROP
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp -s 192.168.1.100 -j DROP
|
||||
```
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 443 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
les -A INPUT -p tcp -m multiport --dport 22,443,80,3306 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp -m multiport --dport 22,443,80,3306 -d 192.168.10.0/24 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -A INPUT -p tcp --dport 80 -m limit --limit 100/minute --limit-burst 200 -j ACCEPT
|
||||
```
|
||||
|
||||
```bash
|
||||
iptables -t NAT -A PREROUTING -i ens33 -p tcp --dport 80 -j REDIRECT --to-port 443
|
||||
```
|
||||
Reference in New Issue
Block a user