ASA Static IP Tunnels

Static IP Tunnel Configuration Generator for ASAs and AnyConnect VPN

This repo contains helper functions designed to generate static IP tunnel configurations for the ASA CLI.

High level design of static IP tunnels on the ASA in tandem with AnyConnect VPN:

  VPN Client "a"             VPN Client "b"
         |                          |
         v                          v
https://<vpn-device>/a     https://<vpn-device>/b
         |                          |
         v                          v
   tunnel-group a ----------- tunnel-group b ---> shared group-policy
         |                          |          -> shared DAP                                
         v                          v
     ip pool a  ->  10.0.0.1    ip pool b -> 10.0.0.2
         |                          |
         v                          v
     Connected!                 Connected!

Please take note of the DAP LUA configuration that goes along with this:

EVAL(cisco.aaa.username, "EQ", cisco.aaa.tunnelgroup)

This is a security necessity to ensure static IPs are taken by the users intended.

The original intent for this program was to satisfy India's VoIP exception for users with static IPs due to COVID-19.

Installation

This code requires Python 3 and has been tested with Python 3.7.7.

git clone [email protected]:CiscoDevNet/asa-static-ip-tunnels.git
cd asa-static-ip-tunnels/
python -m venv venv
source venv/bin/activate
pip install -r requirements.txt

To Run

python asa_static_ip_tunnels.py

The following constants are declared in "__main__" of asa_static_ip_tunnels.py:

START_IP = '10.0.0.1'   # first IP address in IP pool, increments by 1 for each user
DEVICE = 'vpn-device'   # hostname of the VPN headend
AAA_SERVER = 'AAA_Server'   # name of the AAA server declared on the ASA
GROUP_POLICY = 'Default_Group_Policy'   # group policy shared by all static tunnels

The program starts by pulling users from users.txt:

cecId1
cecId2
cecId3
cecId4
cecId5

User IDs can be separated by or \n characters.

Based off the constants and users, CLI configuration is generated in the output/ folder.

filename: output/config.txt

ip local pool cecId1 10.0.0.1 mask 255.255.255.255   ! address pool with single IP
tunnel-group cecId1 type remote-access   ! unique tunnel group with same name as user ID
tunnel-group cecId1 general-attributes
  address-pool cecId1
  authentication-server-group AAA_Server
  default-group-policy Default_Group_Policy
tunnel-group cecId1 webvpn-attributes
  group-url https://vpn-device/cecId1 enable  ! connection URL for user

...

A file labeled clear_config.txt is also created, which contains ASA CLI configuration to undo the static IP tunnels created.

Running asa_static_ip_tunnels.py again overwrites the files in the output/ folder.

Technologies & Frameworks Used

Cisco Products & Services:

ASA OS Software
AnyConnect VPN Client

Tools & Frameworks:

Python 3.7
ipaddress module

File Structure

.
├── asa_static_ip_tunnels.py (where __main__ lies and a code explanation on how to use functions)
├── users.txt (input file for user IDs)
├── static_tunnels.py (configuration generation functions)
├── output (configuration output)
|   ├── config.txt (creation)
|   └── clear_config.txt (deletion)

Authors & Maintainers

Drew Taylor [email protected]

Credits

Damien Stenning [email protected]
Nishant Singh [email protected]
Pete Davis [email protected]
Fernando De Jesus Sancho Vargas [email protected]
Tejas Amin [email protected]

License

This project is licensed to you under the terms of the Cisco Sample Code License.

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