Sunday, March 19, 2023

How To Setup Ipsec VPN

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Establishing And Verifying The Ipsec VPN Tunnel

Tutorial: IPSec VPN Setup

At this point, weve completed our configuration and the VPN Tunnel is ready to be brought up.; To initiate the VPN Tunnel, we need to force one packet to traverse the VPN and this can be achieved by pinging from one router to another:

ping source fastethernet0/0.!!!!

The first icmp echo received a timeout, but the rest received a reply, as expected. The time required to bring up the VPN Tunnel is sometimes slightly more than 2 seconds, causing the first ping to timeout.

To verify the VPN Tunnel, use the show crypto session command:

show crypto session

Configure VPN Server Firewall And Routing

If UFW is enabled and running, configure it to allow and forward the VPN traffic. For IPsec to work through firewall, you need to open UDP ports 500 and 4500.

  • 500/udp Allows Internet Security Association and Key Management Protocol traffic to be forwarded
  • 4500/udp Allows handling of IPsec between natted devices
ufw allow 500/udp

Next, find your server default route interface.

ip route show default
default via dev enp0s3 

In this case, our interface for routing traffic is enp0s3. This interface will be used next while configuring UFW routing as shown below.

Edit the UFW before rules file, /etc/ufw/before.rules and add the lines highlighted below immediately before and after the;*filter.

vim /etc/ufw/before.rules
...####*nat-A POSTROUTING -s -o enp0s3 -m policy --pol ipsec --dir out -j ACCEPT-A POSTROUTING -s -o enp0s3 -j MASQUERADECOMMIT*mangle-A FORWARD --match policy --pol ipsec --dir in -s -o enp0s3 -p tcp -m tcp --tcp-flags SYN,RST SYN -m tcpmss --mss 1361:1536 -j TCPMSS --set-mss 1360COMMIT# Don't delete these required lines, otherwise there will be errors*filter:ufw-before-input - :ufw-before-output - :ufw-before-forward - :ufw-not-local - # End required lines-A ufw-before-forward --match policy --pol ipsec --dir in --proto esp -s -j ACCEPT-A ufw-before-forward --match policy --pol ipsec --dir out --proto esp -d -j ACCEPT...

Disable and enable ufw for the changes to take effect.

How To Setup VPN Ipsec Between Dsr

Devices Used:

  • DSR1: WAN LAN:
  • DSR2: WAN LAN:

WAN and LAN Setup:

Step 1 Setup WAN port setup DSR1

SETUP > Internet Settings > WAN1 Settings > WAN1 Setup

Step 2 Here you will need to select the ISP Connection Type

In our example we have selected Static

Once configured click Save Settings

Step 3 Setup LAN Configuration DSR1

SETUP > Network Setting > LAN Setup Configuration

Step 4 Enter an IP address for the LAN interface and DHCP Server

In our example we have given the IP:

Once configured click Save Settings

Step 5 Setup WAN port setup DSR2

SETUP > Internet Settings > WAN1 Settings > WAN1 Setup

Step 6 Here you will need to select the ISP Connection Type;

In our example we have selected Static

Once configured click Save Settings

Step 7 Setup LAN Configuration DSR1

SETUP > Network Setting > LAN Setup Configuration

Step 8 Here you will need to select the ISP Connection Type

In our example we have selected Static

Once configured click Save Settings

VPN IPsec Setup DSR1:

Step 9 You will now need to setup an IPsec Policy

SETUP > VPN Settings > IPSec > IPsec Policies

Step 10 Click on Add to configure an IPsec Policy

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Setting Up The VPN Server

On the Windows 2012 machine, we will need to install the routing and remote access features. To do so, go in to the Server manager, and Add Roles and Features. Choose a role based or feature based installation.; Select the local server. Choose to install the following server roles.;

Network Policy and Access Services

;;;;;;;;;;; Network Policy Server

;;;;;;;;;;; Direct Access and VPN

;;;;;;;;;;; Routing

Once these new features are installed, you will require a snap in to manage them. Open mmc.exe as an administrator. Go to File | Add/Remove Snap In. Add the routing and remote access snap in.;

This snap in allows the configuration of multi-protocol LAN-to-LAN, LAN-to-WAN, virtual private network , and network address translation routing services.;

In the mmc console, right click on routing and remote access and choose to add server. Choose the local machine. Next, right click on the newly created machine and choose Configure and Enable Routing and Remote Access. Choose the Remote Access.

Then check the VPN option. You must have at least two network cards for this to work. One of them can be a loopback.; Specify a range of addresses to be provided for the incoming connection. Make sure they do not conflict with any other addresses allocated on your existing network. In this example, we will not be using a radius server.

Next, attempt to startthe routing and remote access service.;The following registry key may need to be deleted to start the service.

Choose the authentication methods as shown below.

Creating The Second VPN Gateway

How to Configure a Client

You now need to create the endpoint of the VPN tunnel. If this is a different VDC or vOrg, go through the steps described above again to create the tunnel. When you’ve done that, you can change your firewall settings and validate the connection .

If you’re connecting to an external data centre, you’ll need to set up the tunnel on that premises.

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Setup Secrets For Ike/ipsec Authentication

Next, setup the secrets to be used by the strongSwan Internet Key Exchange daemons to authenticate other hosts. These credentials;are set in the;/etc/ipsec.secrets;configuration file.

Thus open this file and define the RSA private keys for authentication. You can also setup the EAP user credentials by defining a random username and its password.;Note the Spacing.

vim /etc/ipsec.secrets
# This file holds shared secrets or RSA private keys for authentication.# RSA private key for this host, authenticating it to any other host which knows the public part.: RSA vpn_server_key.pem ## Specify the VPN Server Key# Define the list of IDs followed by a secret for authentication# user id : EAP secret       # this file is managed with debconf and will contain the automatically created private keyinclude /var/lib/strongswan/     

Running strongSwan

Save the configuration file above and restart strongswan for the changes above to take effect.

systemctl restart strongswan

To check the status;

systemctl status strongswan

Network Address Translation And Ipsec VPN Tunnels

Network Address Translation is most likely to be configured to provide Internet access to internal hosts. When configuring a Site-to-Site VPN tunnel, it is imperative to instruct the router not to perform NAT on packets destined to the remote VPN network.

This is easily done by inserting a deny statement at the beginning of the NAT access lists as shown below:

For Site 1s router:

ip nat inside source list 100 interface fastethernet0/1 overloadaccess-list 100 remark -==-access-list 100 deny ip 100 permit ip anyaccess-list 100 remark

And Site 2s router:

ip nat inside source list 100 interface fastethernet0/1 overloadaccess-list 100 remark -==-access-list 100 deny ip ; 100 permit ip anyaccess-list 100 remark

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Remote Ike Ids And Dynamic Endpoint VPNs

For dynamic endpoint VPNs, the remote peers expectedIKE ID is configured with the options at the hierarchylevel. For AutoVPN, hostname combined with ike-user-typegroup-ike-id can be used where there are multiple peers thathave a common domain name. If certificates are used for verifyingthe peer, a DN can be configured.

Macos Send Traffic Over VPN

Fortinet: How to Setup a Route-Based IPSec VPN Tunnel on a FortiGate Firewall

OS X users: If you can successfully connect using IPsec/L2TP mode, but your public IP does not show Your VPN Server IP, read the OS X section above and complete these steps. Save VPN configuration and re-connect.

  • Click the Advanced button and make sure the Send all traffic over VPN connection checkbox is checked.
  • Click the TCP/IP tab, and make sure Link-local only is selected in the Configure IPv6 section.
  • After trying the steps above, if your computer is still not sending traffic over the VPN, check the service order. From the main network preferences screen, select “set service order” in the cog drop down under the list of connections. Drag the VPN connection to the top.

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    How To Setup L2tp VPN Connection In Linux

    To add an L2TP/IPsec option to the NetworkManager, you need to install the NetworkManager-l2tp VPN plugin which supports NetworkManager 1.8 and later. It provides support for L2TP and L2TP/IPsec.

    To install the L2TP module on Ubuntu and Ubuntu-based Linux distributions, use the following PPA.

    $ sudo add-apt-repository ppa:nm-l2tp/network-manager-l2tp$ sudo apt-get update$ sudo apt-get install network-manager-l2tp  network-manager-l2tp-gnome

    On RHEL/CentOS and Fedora Linux, use the following dnf command to install L2TP module.

    # dnf install xl2tpd# dnf install NetworkManager-l2tp# dnf install NetworkManager-l2tp-gnomeOR# yum install xl2tpd# yum install NetworkManager-l2tp# yum install NetworkManager-l2tp-gnome

    Once the package installation is complete, click on your Network Manager icon, then go to Network Settings.

    Next, add a new VPN connection by clicking on the sign.

    Then select Layer 2 Tunneling Protocol option from the pop-up window.

    Next, enter the VPN connection details you received from the system administrator, in the following window.

    Next, click IPsec Settings to enter the pre-shared key for the connection. Then enable IPsec tunnel to L2TP host, enter the Pre-shared key and click Ok.

    After that, click Add. Now your new VPN connection should be added.

    Next, turn on the VPN connection to start using it. If the connection details are correct, the connection should be established successfully.

    Creating An External Data Centre VPN Gateway

    Although we can’t provide specific instructions on setting up an external data centre gateway to connect to the edge gateway, we’ve provided information about some configuration requirements below.

    • IPsec VPN supports only time-based rekeying. You must disable lifebytes rekeying.

    • Starting in NSX 6.4.5, Triple DES cypher algorithm is deprecated in IPsec VPN.

    IKE Phase 1 and Phase 2

    IKE is a standard method for arranging secure, authenticated communications.

    Phase 1 parameters

    Phase 1 sets up mutual authentication of the peers, negotiates cryptographic parameters, and creates session keys. The supported Phase 1 parameters are:

    • Main mode

    • SA lifetime of 28800 seconds with no kbytes rekeying

    • ISAKMP aggressive mode disabled

    Phase 2 parameters

    IKE Phase 2 negotiates an IPsec tunnel by creating keying material for the IPsec tunnel to use . The supported IKE Phase 2 parameters are:

    • AES/AES256/AES-GCM

    • ESP tunnel mode

    • Perfect forward secrecy for rekeying

    • SA lifetime of 3600 seconds with no kbytes rekeying

    • Selectors for all IP protocols, all ports, between the two networks, using IPv4 subnets

    Read Also: Why My VPN Is Not Working

    Cisco Ipsec VPN Setup For Iphone And Ipad

    Use this section to configure your Cisco VPN server for use with iOS and iPadOS, both of which support Cisco ASA 5500 Security Appliances and PIX firewalls. iOS and iPadOS also support Cisco IOS VPN routers with IOS version 12.4T or later. VPN 3000 Series Concentrators dont support iOS or iPadOS VPN capabilities.

    Testing Strongswan VPN Connection

    Fortinet: How to Setup a Route

    strongSwan VPN server has been setup. You can now proceed to test the IP assignment and local connection via the VPN server.

    See our next guide on how to setup strongSwan VPN client on Ubuntu 18.04 and CentOS 8.

    That marks the end of our guide on how to setup IPSEC VPN using StrongSwan on Debian 10 Buster.

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    L2tp/ipsec Remote Access VPN Configuration Example

    On current versions of pfSense® software, L2TP/IPsec may be configured formobile clients, though it is not a configuration we recommend.


    Users have reported issues with Windows L2TP/IPsec clients behindNAT. If the clients will be behind NAT, Windows clients will most likely notfunction. Consider an IKEv2 implementation instead.

    As warned at the start of the chapter, the Windows client, among others, and thestrongSwan IPsec daemon are not always compatible, leading to failure in manycases. We strongly recommend using another solution such as IKEv2 instead ofL2TP/IPsec.

    See also

    Windows Error 789 Or 691

    Error 789: The L2TP connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer.

    Error 691: The remote connection was denied because the user name and password combination you provided is not recognized, or the selected authentication protocol is not permitted on the remote access server.

    For error 789, click here for troubleshooting information. For error 691, you may try removing and recreating the VPN connection, by following the instructions in this document. Make sure that the VPN credentials are entered correctly.

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    Cisco Ipsec VPN Client Windows 10 Alternative

    DH Exchange should match DH Group.

    Cipher Algorithm should match Encryption Algorithm.

    Hash Algorithm should match Authentication Algorithm.

    Step 12. If your gateway offers a Cisco compatible vendor ID during phase1 negotiations, check the Enable Check Point Compatible Vendor ID check box. If the gateway does not, or you are unsure, leave the check box unchecked.

    Step 13. Click on the Phase 2 tab. Configure the following parameters to have the same settings that you configured for the RV130/RV130W in Step 2 of the IPSec VPN Server User Configuration section of this document.

    The parameters in Shrew Soft should match the RV130/RV130W configurations in Phase 2 as follows:

    Transform Algorithm should match Encryption Algorithm.

    HMAC Algorithm should match Authentication Algorithm.

    PFS Exchange should match DH Group if PFS Key Group is enabled on the RV130/RV130W. Otherwise, select disabled.

    Key Life Time limit should match IPSec SA Lifetime.

    Step 14. Click on the Policy tab and select require in the Policy Generation Level drop-down list. The Policy Generation Level option modifies the level in which IPsec Policies are generated. The different levels provided in the drop-down list map to IPSec SA negotiation behaviors implemented by different vendor implementations.

    The available options are defined as follows:

    Auto The client will automatically determine the appropriate IPSec Policy Level.

    The Topology Entry window appears:

    Apply Crypto Map To The Public Interface

    30. Configure Site to site L2TP/IPSEC VPN in Windows Server 2019

    The final step is to apply the crypto map to the outgoing interface of the router. Here, the outgoing interface is FastEthernet 0/1.

    interface FastEthernet0/1crypto map CMAP

    Note that you can assign only one crypto map to an interface.

    As soon as we apply crypto map on the interface, we receive a message from the router ;that confirms isakmp is on: ISAKMP is ON.

    At this point, we have completed the IPSec VPN configuration on the Site 1 router.

    We now move to the Site 2 router to complete the VPN configuration. The settings for Router 2 are identical, with the only difference being the peer IP Addresses and access lists:

    crypto isakmp policy 1encr 3descrypto map CMAP

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    Configuring Remote Ike Ids For Site

    To modify the configuration of the SRX Series deviceor the peer device for the IKE ID that is used:

    • On the SRX Series device, configure the remote-identity statement at the hierarchy level to match the IKE ID that is received fromthe peer. Values can be an IPv4 or IPv6 address, FQDN, distinguishedname, or e-mail address.

      If you do not configure remote-identity, the deviceuses the IPv4 or IPv6 address that corresponds to the remote peerby default.

    • On the peer device, ensure that the IKE ID is the sameas the remote-identity configured on the SRX Series device.If the peer device is an SRX Series device, configure the local-identity statement at the hierarchy level. Values can be an IPv4 or IPv6 address, FQDN,distinguished name, or e-mail address.

    Windows Error 628 Or 766

    Error 628: The connection was terminated by the remote computer before it could be completed.

    Error 766: A certificate could not be found. Connections that use the L2TP protocol over IPSec require the installation of a machine certificate, also known as a computer certificate.

    To fix these errors, please follow these steps:

  • Right-click on the wireless/network icon in your system tray.
  • Select Open Network and Sharing Center. Or, if using Windows 10 version 1709 or newer, select Open Network & Internet settings, then on the page that opens, click Network and Sharing Center.
  • On the left, click Change adapter settings. Right-click on the new VPN and choose Properties.
  • Click the Security tab. Select “Layer 2 Tunneling Protocol with IPsec ” for Type of VPN.
  • Click Allow these protocols. Check the “Challenge Handshake Authentication Protocol ” and “Microsoft CHAP Version 2 ” checkboxes.
  • Click the Advanced settings button.
  • Select Use preshared key for authentication and enter Your VPN IPsec PSK for the Key.
  • Click OK to close the Advanced settings.
  • Click OK to save the VPN connection details.
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    Before You Get Started

    • What is your VCN’s CIDR? ;

      What is the public IP address of your CPE device? If you have multiple devices for redundancy, get the IP address for each.

      Note:If your CPE device is behind a NAT device, see Overview of Site-to-Site VPN Components and also Requirements and Prerequisites.

      Will you use port address translation between each CPE device and your VCN? ;

      What type of routing do you plan to use? If you want BGP dynamic routing, list the BGP session IP addresses to use and the ASN of your network. The IP addresses must be part of Site-to-Site VPN’s encryption domain.

      If you want static routing, what are the static routes for your on-premises network? See Routing for Site-to-Site VPN.

      Do you plan to use policy based routing or multiple encryption domains? See Encryption domains for policy-based tunnels.


      Do you want to provide each tunnel’s shared secret or let Oracle assign them? See Overview of Site-to-Site VPN Components.

    • Draw a diagram of your network layout . Think about which parts of your on-premises network need to communicate with your VCN, and the reverse. Map out the routing and security rules that you need for your VCN.


    Setup Cisco Ipsec VPN Windows 10

    How to successfully configure Cisco site

    Note: By providing WINS configuration information, a client will be able to resolve WINS names using a server located in the remote private network. This is useful when attempting to access remote windows network resources using a Uniform Naming Convention path name. The WINS server would typically belong to a Windows Domain Controller or a Samba Server.

    Step 9. Click on the Authentication tab, and select Mutual PSK + XAuth in the Authentication Method drop-down list.

    The available options are defined as follows:

    Hybrid RSA + XAuth The client credential is not needed. The client will authenticate the gateway. The credentials will be in the form of PEM or PKCS12 certificate files or key files type.

    Hybrid GRP + XAuth The client credential is not needed. The client will authenticate the gateway. The credentials will be in the form of PEM or PKCS12 certificate file and a shared secret string.

    Mutual RSA + XAuth Client and gateway both need credentials to authenticate. The credentials will be in the form of PEM or PKCS12 certificate files or key type.

    Mutual PSK + XAuth Client and gateway both need credentials to authenticate. The credentials will be in the form of a shared secret string.

    Mutual RSA Client and gateway both need credentials to authenticate. The credentials will be in the form of PEM or PKCS12 certificate files or key type.

    The parameters in Shrew Soft should match the RV130/RV130W configurations in Phase 1 as follows:

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