Tunnel vision: Choosing a VPN -- SSL VPN vs. IPSec VPN

Continue Reading This Article

VPNs and VPN Technologies
Azure Cloud Shell's browser-based model frees IT teams from installation headaches but presents some formatting and timeout Lisa Phifer is vice president with Core Competence, a consulting firm specializing in network security and management technology. In order to decide what protection is to be provided for an outgoing packet, IPsec uses the Security Parameter Index SPI , an index to the security association database SADB , along with the destination address in a packet header, which together uniquely identifies a security association for that packet. Retrieved August 19, IPsec uses the following protocols to perform various functions:

Navigation menu

IPsec VPN Overview

It was chosen as the default because it is used less frequently than other RFC address blocks, and thus is less likely to conflict with existing address assignments on your network. If you use GRE to connect multiple Untangle servers together, you may need to configure a different, unused pool on each server. There will typically be two entries per tunnel, one with details about the local side of the connection, and another with details about the remote side of the connection.

The IPsec Log tab allows you to see the low level status messages that are generated by the underlying IPsec protocol components. This information can be very helpful when attempting to diagnose connection problems or other IPsec issues.

This information can be very helpful when attempting to diagnose connection problems or other L2TP issues. This applications reports can be accessed via the Reports tab at the top or the Reports tab within the settings. All pre-defined reports will be listed along with any custom reports that have been created. Reports can be searched and further defined using the time selectors and the Conditions window at the bottom of the page.

The data used in the report can be obtained on the Current Data window on the right. When using tunnel mode, you can think of the payload packet as being completely encased in another packet. In addition, IPsec can allow or deny packets access to the tunnel depending on policies. When using transport mode, communication is limited between two hosts. Only one IP header is present, with the rest of the packet being encrypted. Unless you have very specific needs, you'll most likely want to use tunnel mode.

We have user-submitted settings for other devices below, but please be aware Untangle Support cannot debug tunnels between Untangle and a 3rd party device. We only support IPsec tunnels between two Untangle boxes. You may also need to enable NAT traversal. However, technically it can work with DHCP, but you will need to reconfigure the tunnel whenever the IP address actually changes.

However, if you want IPsec tunnel traffic to bypass scanning by other applications you can add a bypass rule. In versions prior to You may still have a bypass rule in place to Bypass all IPsec traffic which will cause the traffic to not be scanned by other apps. IPsec on Untangle should work with any compatible endpoint, but unfortunately Untangle doesn't have the resources to test against all known IPSec devices. Untangle support has successfully deployed IPSec connections to various models from the following 3rd party manufacturers:.

Retrieved from " https: Personal tools Log in. Navigation Main page Recent changes Random page Help. This field allows you to set the connection type to any of the following: You can choose your key creation mechanism—also called authentication method—during Phase 1 and Phase 2 proposal configuration. See IPsec Tunnel Negotiation. With manual keys, administrators at both ends of a tunnel configure all the security parameters.

This is a viable technique for small, static networks where the distribution, maintenance, and tracking of keys are not difficult. However, safely distributing manual-key configurations across great distances poses security issues. Aside from passing the keys face-to-face, you cannot be completely sure that the keys have not been compromised while in transit. Also, whenever you want to change the key, you are faced with the same security issues as when you initially distributed it.

When you need to create and manage numerous tunnels, you need a method that does not require you to configure every element manually. IPsec supports the automated generation and negotiation of keys and security associations using the Internet Key Exchange IKE protocol. In this regard, the issue of secure key distribution is the same as that with manual keys. However, once distributed, an autokey, unlike a manual key, can automatically change its keys at predetermined intervals using the IKE protocol.

Frequently changing keys greatly improves security, and automatically doing so greatly reduces key-management responsibilities. However, changing keys increases traffic overhead; therefore, changing keys too often can reduce data transmission efficiency.

A preshared key is a key for both encryption and decryption, which both participants must have before initiating communication. AutoKey IKE with certificates—When using certificates to authenticate the participants during an AutoKey IKE negotiation, each side generates a public-private key pair and acquires a certificate. A Diffie-Hellman DH exchange allows participants to produce a shared secret value.

The strength of the technique is that it allows participants to create the secret value over an unsecured medium without passing the secret value through the wire. The size of the prime modulus used in each group's calculation differs as follows:. Because the modulus for each DH group is a different size, the participants must agree to use the same group.

Authentication Header AH —A security protocol for authenticating the source of an IP packet and verifying the integrity of its content. You can choose your security protocols—also called authentication and encryption algorithms —during Phase 2 proposal configuration. Tunnel sessions are updated with the negotiated protocol after negotiation is completed. ESP and AH tunnel sessions are displayed in the outputs for the show security flow session and show security flow cp-session operational mode commands.

The Authentication Header AH protocol provides a means to verify the authenticity and integrity of the content and origin of a packet. Message Digest 5 MD5 —An algorithm that produces a bit hash also called a digital signature or message digest from a message of arbitrary length and a byte key. The resulting hash is used, like a fingerprint of the input, to verify content and source authenticity and integrity. Secure Hash Algorithm SHA —An algorithm that produces a bit hash from a message of arbitrary length and a byte key.

It is generally regarded as more secure than MD5 because of the larger hashes it produces. Because the computational processing is done in the ASIC, the performance cost is negligible. The Encapsulating Security Payload ESP protocol provides a means to ensure privacy encryption and source authentication and content integrity authentication.

ESP in tunnel mode encapsulates the entire IP packet header and payload and then appends a new IP header to the now-encrypted packet. This new IP header contains the destination address needed to route the protected data through the network. With ESP, you can both encrypt and authenticate, encrypt only, or authenticate only. For encryption, you can choose one of the following encryption algorithms:. DES provides significant performance savings but is considered unacceptable for many classified or sensitive material transfers.

Overview of VPNs and VPN Technologies

Leave a Reply