Main Menu
  • COMPANY
    • Boundless Cybersecurity
    • Press Releases
    • News
    • Awards
    • Leadership
    • Press Kit
    • Careers
  • PROMOTIONS
    • Customer Loyalty Program
  • MANAGED SERVICES
    • Managed Security Services
    • Security as a Service
    • Professional Services
SonicWall
  • Products
    • Network Security
      • Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
      • Security ServicesComprehensive security for your network security solution
      • Network Security ManagerModern Security Management for today’s security landscape
    • Advanced Threat Protection
      • Capture ATPMulti-engine advanced threat detection
      • Capture Security applianceAdvanced Threat Protection for modern threat landscape
    • Access Security
      • Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
      • Secure Mobile AccessRemote, best-in-class, secure access
      • Wireless Access PointsEasy to manage, fast and secure Wi-FI
      • SwitchesHigh-speed network switching for business connectivity
    • Email Security
      • Email SecurityProtect against today’s advanced email threats
    • Cloud Security
      • Cloud App SecurityVisibility and security for Cloud Apps
      • Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
    • Endpoint Security
      • Capture ClientStop advanced threats and rollback the damage caused by malware
      • Content Filtering ClientControl access to unwanted and unsecure web content
    • Product Widgets
      • Product Menu Right Image
      • Capture Cloud Platform
        Capture Cloud Platform

        A security ecosystem to harness the power of the cloud

    • Button Widgets
      • Products A-Z
        all products A–Z FREE TRIALS
  • Solutions
    • Industries
      • Distributed Enterprises
      • Retail & Hospitality
      • K-12 Education
      • Higher Education
      • State & Local
      • Federal
      • Healthcare
      • Financial Services
      • Carriers
    • Use Cases
      • Secure SD-Branch
      • Zero Trust Security
      • Secure SD-WAN
      • Office 365 Security
      • SaaS Security
      • Secure WiFi
    • Solutions Widgets
      • Solutions Content Widgets
        Federal

        Protect Federal Agencies and Networks with scalable, purpose-built cybersecurity solutions

      • Solutions Image Widgets
  • Partners
    • SonicWall Partners
      • Partners Overview
      • Find a Partner
      • Authorized Distributors
      • Technology Partners
    • Partner Resources
      • Become a Partner
      • SonicWall University
      • Training & Certification
    • Partner Widgets
      • Custom HTML : Partners Content WIdgets
        Partner Portal

        Access to deal registration, MDF, sales and marketing tools, training and more

      • Partners Image Widgets
  • Support
    • Support
      • Support Portal
      • Knowledge Base
      • Technical Documentation
      • Community
      • Video Tutorials
      • Product Life Cycle Tables
      • Partner Enabled Services
      • Contact Support
    • Resources
      • Resource Center
      • Free Trials
      • Blog
      • SonicWall University
      • MySonicWall
    • Capture Labs
      • Capture Labs
      • Security Center
      • Security News
      • PSIRT
      • Application Catalog
    • Support Widget
      • Custom HTML : Support Content WIdgets
        Support Portal

        Find answers to your questions by searching across our knowledge base, community, technical documentation and video tutorials

      • Support Image Widgets
  • COMPANY
    • Boundless Cybersecurity
    • Press Releases
    • News
    • Awards
    • Leadership
    • Press Kit
    • Careers
  • PROMOTIONS
    • Customer Loyalty Program
  • MANAGED SERVICES
    • Managed Security Services
    • Security as a Service
    • Professional Services
  • Contact Sales
  • English English English en
  • BLOG
  • CONTACT SALES
  • FREE TRIALS
  • English English English en
SonicWall
  • Products
    • Network Security
      • Next Generation FirewallNext-generation firewall for SMB, Enterprise, and Government
      • Security ServicesComprehensive security for your network security solution
      • Network Security ManagerModern Security Management for today’s security landscape
    • Advanced Threat Protection
      • Capture ATPMulti-engine advanced threat detection
      • Capture Security applianceAdvanced Threat Protection for modern threat landscape
    • Access Security
      • Cloud Edge Secure AccessDeploy Zero-Trust Security in minutes
      • Secure Mobile AccessRemote, best-in-class, secure access
      • Wireless Access PointsEasy to manage, fast and secure Wi-FI
      • SwitchesHigh-speed network switching for business connectivity
    • Email Security
      • Email SecurityProtect against today’s advanced email threats
    • Cloud Security
      • Cloud App SecurityVisibility and security for Cloud Apps
      • Cloud Firewall (NSv)Next-generation firewall capabilities in the cloud
    • Endpoint Security
      • Capture ClientStop advanced threats and rollback the damage caused by malware
      • Content Filtering ClientControl access to unwanted and unsecure web content
    • Product Widgets
      • Product Menu Right Image
      • Capture Cloud Platform
        Capture Cloud Platform

        A security ecosystem to harness the power of the cloud

    • Button Widgets
      • Products A-Z
        all products A–Z FREE TRIALS
  • Solutions
    • Industries
      • Distributed Enterprises
      • Retail & Hospitality
      • K-12 Education
      • Higher Education
      • State & Local
      • Federal
      • Healthcare
      • Financial Services
      • Carriers
    • Use Cases
      • Secure SD-Branch
      • Zero Trust Security
      • Secure SD-WAN
      • Office 365 Security
      • SaaS Security
      • Secure WiFi
    • Solutions Widgets
      • Solutions Content Widgets
        Federal

        Protect Federal Agencies and Networks with scalable, purpose-built cybersecurity solutions

      • Solutions Image Widgets
  • Partners
    • SonicWall Partners
      • Partners Overview
      • Find a Partner
      • Authorized Distributors
      • Technology Partners
    • Partner Resources
      • Become a Partner
      • SonicWall University
      • Training & Certification
    • Partner Widgets
      • Custom HTML : Partners Content WIdgets
        Partner Portal

        Access to deal registration, MDF, sales and marketing tools, training and more

      • Partners Image Widgets
  • Support
    • Support
      • Support Portal
      • Knowledge Base
      • Technical Documentation
      • Community
      • Video Tutorials
      • Product Life Cycle Tables
      • Partner Enabled Services
      • Contact Support
    • Resources
      • Resource Center
      • Free Trials
      • Blog
      • SonicWall University
      • MySonicWall
    • Capture Labs
      • Capture Labs
      • Security Center
      • Security News
      • PSIRT
      • Application Catalog
    • Support Widget
      • Custom HTML : Support Content WIdgets
        Support Portal

        Find answers to your questions by searching across our knowledge base, community, technical documentation and video tutorials

      • Support Image Widgets
  • COMPANY
    • Boundless Cybersecurity
    • Press Releases
    • News
    • Awards
    • Leadership
    • Press Kit
    • Careers
  • PROMOTIONS
    • Customer Loyalty Program
  • MANAGED SERVICES
    • Managed Security Services
    • Security as a Service
    • Professional Services
  • Contact Sales
  • Menu

What does the 'NAT Traversal' checkbox do?

10/14/2021 1,179 People found this article helpful 106,422 Views

    Download
    Print
    Share
    • LinkedIn
    • Twitter
    • Facebook
    • Email
    • Copy URL The link has been copied to clipboard

    Description

    NAT Traversal, if enabled, automatically detects if network address translation (NAT) is being performed between the two VPN tunnel endpoints, since this "in-between" NAT can interfere with IPsec/ESP traffic also, some routers that may exist between the VPN peers might be programmed to block IPsec pass-through, or have been programmed to block IP 50 (ESP).

    If NAT is indeed being performed somewhere between those two endpoints, and both endpoints are capable of doing NAT Traversal, the IPsec traffic will be encapsulated within UDP packets. Encapsulating the IPsec traffic in UDP packets allows the IPsec traffic to be NAT'ed in between the endpoints. SonicWall's implementation of NAT Traversal is based upon RFC 3947.

    How it works

    NAT Traversal is achieved by sending the NAT Traversal Vendor ID field in the first two messages in Main Mode and Aggressive Mode. A MD5 Hash (draft-ietf-IPsec-Nat-t-Ike-00) is sent as Vendor ID hash. Upon the receipt of this Vendor ID, both sides can decide whether the other end supports NAT Traversal or not. A new payload called "NAT-Discovery" payload is sent in the message 2 and 3 in Main Mode, and message 2 and message 3 in the Aggressive Mode. The HASH function negotiated in the IKE is used in the HASH calculation: it can be MD5 or SHA.
    After receiving the NATD payload the IPsec Tunnel endpoints can determine whether a NAT security appliance is in between by computing the HASH values locally and comparing with the HASH values received. If a NAT security appliance is detected in between the endpoints, in the phase 2 Quick mode instead of ESP Attribute, UDP_TUNNEL_ESP -| 61443 or UDP_TRANSPORT_ESP -| 61444 is sent depending on Tunnel/Transport mode. If a NAT security appliance is not detected then there is no change in the Quick Mode.

    Once the IPSEC SA is negotiated in the Quick Mode, the ESP packets should be encapsulated in the UDP header. The UDP encapsulation should use the same source and destination port as used in the IKE negotiations however, in draft 3, the UDP port is floated to 4500. The UDP encapsulation should be done only when a NAT security appliance is present in between the endpoints. The Phase 1 initiator will send the keep alives. The Keep Alive is just to keep up the NAPT mapping with the NAT security appliance in between.

    Resolution

    Resolution for SonicOS 6.5

    This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.

    Image 

    To find NAT Traversal setting Login to SonicWall Device.

    1. Click Manage in the top navigation menu.
    2. Click  VPN | Advanced Settings.
      Image



    Resolution for SonicOS 6.2 and Below

    The below resolution is for customers using SonicOS 6.2 and earlier firmware. For firewalls that are generation 6 and newer we suggest to upgrade to the latest general release of SonicOS 6.5 firmware.

     

    Image
    You can find NAT Traversal setting under VPN | Advanced.
    Image

    Related Articles

    • Analyzing TCP reset(RST)packets
    • ‘Error sending one-time password’ encountered when connecting to NetExtender
    • Supported SonicWall and 3rd party SFP and SFP+ modules that can be used with SonicWall NSsp series

    Categories

    • Firewalls > SonicWall NSA Series > VPN
    • Firewalls > SonicWall SuperMassive 9000 Series > VPN
    • Firewalls > TZ Series > VPN
    • Firewalls > NSa Series > VPN
    • Firewalls > NSv Series > VPN

    Not Finding Your Answers?

    ASK THE COMMUNITY

    Was This Article Helpful?

    YESNO

    Article Helpful Form

    Article Not Helpful Form

    Company
    • Careers
    • News
    • Leadership
    • Awards
    • Press Kit
    • Contact Us
    Popular resources
    • Communities
    • Blog
    • SonicWall Capture Labs

    Stay In Touch

    • By submitting this form, you agree to our Terms of Use and acknowledge our Privacy Statement. You can unsubscribe at any time from the Preference Center.
    • This field is for validation purposes and should be left unchanged.
    • Facebook
    • Twitter
    • Linkedin
    • Youtube
    • Instagram

    © 2022 SonicWall. All Rights Reserved.

    • Legal
    • Privacy
    • English
    Scroll to top
    Trace:4ee82ce2006b54d95245027ae7978e4a-89