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Arris NVG558 Router - Firewall - Service Blocking / ALG

2026-10-15 04:56:30.568

Arris NVG558 Router - Firewall - Service Blocking / ALG

Here's how to setup service blocking / ALG on your NVG558 router.

Service Blocking

  1. Sign in to the Admin WebGUI then click
    Firewall
    .
    You must be connected to the network to access the admin page.
  2. Click
    Service Blocking.
  3. Configure the following:
    • Enable Service Blocking
      : When enabled, the services in the list are blocked from LANside clients. The button name changes to
      Disable Service Blocking
      .
    • Select Service From List
      : Select services from the pull-down list to be blocked. A custom service can be blocked by creating a name and port.
    • Trusted IP
      : Manually enter the LAN-side IP address of clients to be trusted and not have services blocked.
    Firewall - Service Blocking

Application Level Gateway (ALG)

  1. Sign in to the Admin WebGUI then click
    Firewall
    .
    You must be connected to the network to access the admin page.
  2. Click
    ALG
    .
  3. Configure the following then click
    Save
    :
    • FTP
      : When enabled, provides support for File Transfer Protocol.
    • H.323
      : When enabled, provides audio-visual communications support.
    • TFTP
      : When Trivial File Transfer Protocol is enabled, it allows get/put of a file from/to a remote host.
    • PPTP
      : When Point-to-Point Tunneling is enabled, it supports virtual private networking.
    • IPSec
      : This feature helps ESP (IPsec encryption) work properly when using NAT. It can sometimes cause problems for non-NATed hosts (such as devices on the Public LAN).
    • SIP
      : This feature understands the SIP protocol used by the specific applications and does a protocol packet-inspection of traffic through it. A NAT router with a built-in SIP ALG can re-write information within the SIP messages (SIP headers and SDP body) making signaling and audio traffic between the client behind NAT and the SIP endpoint possible.
    Firewall - ALG