Overview

Readers will learn how to configure a site-to-site VPN between two EdgeRouters that use dynamic public IP addresses.

Table of Contents

1. Frequently Asked Questions (FAQ)
2. Configuring a Policy-Based VPN using FQDNs
3. Related Articles

FAQ

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1. What Site-to-Site IPsec VPN types can be configured on EdgeOS? The following IPsec VPN types can be configured on EdgeOS: Policy-Based Route-Based (VTI) GRE over IPsec

2. What are the available encryption and hashing options (Security Associations / SAs) for Phase 1 (IKE) and Phase 2 (ESP)? Encryption AES128 AES256 AES128GCM128 AES256GCM128 3DES Hashing MD5 SHA1 SHA2-256 SHA2-384 SHA2-512

Configuring a Policy-Based VPN using FQDNs

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The 192.168.1.0/24 and 172.16.1.0/24 networks will be allowed to communicate with each other over the VPN.

Follow the steps below to configure the Policy-Based Site-to-Site IPsec VPN on both EdgeRouters:

1. Define the IPsec peer and hashing/encryption methods.

VPN > IPsec Site-to-Site > +Add Peer

• Check: Show advanced options
• Check: Automatically open firewall and exclude from NAT

Peer: er-r.ubnt.com
Description: ipsec
Local IP: 0.0.0.0
Encryption: AES-128
Hash: SHA1
DH Group: 14
Pre-shared Secret: <secret>
Local subnet: 192.168.1.0/24
Remote subnet: 172.16.1.0/24 

2. Apply the changes.

1. Define the IPsec peer and the hashing/encryption methods.

VPN > IPsec Site-to-Site > +Add Peer

• Check: Show advanced options
• Check: Automatically open firewall and exclude from NAT

Peer: er-l.ubnt.com
Description: ipsec
Local IP: 0.0.0.0
Encryption: AES-128
Hash: SHA1
DH Group: 14
Pre-shared Secret: <secret>
Local subnet: 172.16.1.0/24 
Remote subnet: 192.168.1.0/24

2. Apply the changes.

Depending on your setup, optionally add the following additional configuration:

1. Use the dhcp-interface command instead of local-address.

configure
delete vpn ipsec site-to-site peer er-r.ubnt.com local-address
set vpn ipsec site-to-site peer er-r.ubnt.com dhcp-interface eth0
commit ; save

2. Add remote and local authentication IDs.

configure
set vpn ipsec site-to-site peer er-r.ubnt.com authentication id @er-l.ubnt.com
set vpn ipsec site-to-site peer er-r.ubnt.com authentication remote-id @er-r.ubnt.com
commit ; save

3. Change from pre-shared key to certificate-based authentication.

generate vpn rsa-key

configure
set vpn rsa-keys local-key file /config/ipsec.d/rsa-keys/localhost.key
set vpn rsa-keys rsa-key-name er-r rsa-key <er-r public key>

delete vpn ipsec site-to-site peer er-r.ubnt.com authentication mode
delete vpn ipsec site-to-site peer er-r.ubnt.com authentication pre-shared-secret

set vpn ipsec site-to-site peer er-r.ubnt.com authentication mode rsa
set vpn ipsec site-to-site peer er-r.ubnt.com authentication rsa-key-name er-r
commit ; save

1. Use the dhcp-interface command instead of local-address.

configure
delete vpn ipsec site-to-site peer er-l.ubnt.com local-address
set vpn ipsec site-to-site peer er-l.ubnt.com dhcp-interface eth0
commit ; save

2. Add remote and local authentication IDs.

configure
set vpn ipsec site-to-site peer er-l.ubnt.com authentication id @er-r.ubnt.com
set vpn ipsec site-to-site peer er-l.ubnt.com authentication remote-id @er-l.ubnt.com
commit ; save

3. Change from pre-shared key to certificate-based authentication.

generate vpn rsa-key

configure
set vpn rsa-keys local-key file /config/ipsec.d/rsa-keys/localhost.key
set vpn rsa-keys rsa-key-name er-l rsa-key <er-l public key>

delete vpn ipsec site-to-site peer er-l.ubnt.com authentication mode
delete vpn ipsec site-to-site peer er-l.ubnt.com authentication pre-shared-secret

set vpn ipsec site-to-site peer er-l.ubnt.com authentication mode rsa
set vpn ipsec site-to-site peer er-l.ubnt.com authentication rsa-key-name er-l
commit ; save

Related Articles

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EdgeRouter - Policy-Based IPsec Site-to-Site VPN

EdgeRouter - Route-Based IPsec Site-to-Site VPN

Intro to Networking - How to Establish a Connection Using SSH