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🚀 Update July 2026: New Centro Business 3.0 Firmware "10.04.14" available — fixes the Alcatel/TCL Internet Backup Dongle issue. Details in the Release Note.

Public Addresses (DMZ)

The DMZ function (Public Addresses) assigns a public IP address from the subscribed IP range directly to devices. These devices are then accessible from the Internet without NAT and without port forwarding. The DMZ firewall of the Centro Business protects these devices separately from the rest of the LAN.

Typical use cases​

  • Own web server / mail server: A server needs to be directly accessible from the Internet under a fixed public IP.
  • Local firewall / security gateway: A dedicated hardware firewall (e.g. Sophos, FortiGate) receives a public IP and manages traffic independently.
  • IP camera system with own management: An NVR or camera system requires its own public IP for remote access.
  • VoIP telephone system (PBX): A SIP-based telephone system is operated directly with a public IP to avoid NAT issues.
Are PPP internet connections (with Fixed IP option) regularly interrupted?
n nnYes. Approximately once a week, the PPPoE session is interrupted by the RADIUS server for a few seconds.nn- Time window: approx. every 7–8 days, between 01:00 and 05:00n- Duration: a few seconds (automatic reconnect)nn**Why?**nnSwisscom operates approx. 64,000 PPPoE sessions on 12 ISG servers in Switzerland. Since PPP sessions are static (they remain on the ISG where they initially logged in), an imbalance would occur without periodic disconnects.nnThe so-called "Max-Session-Timer" forces a brief interruption so that:n1. Load balancing: Sessions are evenly distributed across all 12 ISGs, systematically preventing overload on individual servers.n2. Maintenance: Swisscom can cleanly decouple affected sessions when performing maintenance on individual ISG instances (hardware, software, configuration).nn:::tipnThis interruption only affects connections with the "Fixed IP address" option (PPPoE). Standard DHCP connections are not affected.n:::n

Configure DMZ​

The Centro Business 2.0 provides two different DMZ options, which can be activated as follows:

  • On the router portal under Network → Public Addresses
  • Activate the desired DMZ option

Public IP addresses on all LAN ports (DHCP) With this option, the DMZ is activated on all LAN ports (incl. WLAN) of the Centro Business. The local LAN of the router can no longer be used in this mode.​


Public IP addresses on LAN Port 1 (DMZ) With this option, the DMZ is activated on LAN Port 1. The local LAN of the Centro Business can continue to be used on Ports 2–4 as well as via WLAN.​

warning

DMZ Access Rules

  • Access from the DMZ to the LAN is blocked
  • Access from the LAN to the DMZ is via the public IP addresses
  • Access to the router portal is via the LAN network or remote access
  • Access from the DMZ to the router portal is not possible

Limitations​

  • Not available with BNS/EC-S contract

FAQ - DMZ​

What are the advantages of a DMZ?
  • Improved security: By placing publicly accessible servers in the DMZ, the internal network is protected from direct attacks from the Internet.
  • Isolation of services: Services such as web servers, email servers, and DNS servers can be isolated in the DMZ, which simplifies the security and management of these services.
  • Flexibility: The DMZ offers a flexible environment where new services and applications can be tested and deployed without endangering the internal network.
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