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Firewall instructions for your IT team

Firewall configuration - info on ports, protocols, web sockets, whitelisting and more

Henrik Mattsson avatar
Written by Henrik Mattsson
Updated over a week ago


Our live streaming clients (for both IPv4 and IPv6) attempt to connect to our servers via a number of ports, as well as both UDP and TCP.

  • Configure your firewall
    When configuring your firewall the most performant ports to allow are 19305 - 19309 via UDP. This will provide your users with the best connection to Lookback's servers. In the event those ports cannot be opened our application then falls back to port 19305  via TCP, and then port 22466  via TCP. In instances where none of these ports can be reached we will attempt to fall back to port 443  via TCP (in a TLS/SSL tunnel) however this is the least performant of all options so we suggest opening the other ports if possible.

    To reiterate, we suggest opening ports in the following order of preference: 

UDP ports 19305 - 19309
TCP port 19305
TCP port 22466
TCP port 443


If your firewall performs deep packet inspection on port 443  or you cannot open any of the other ports listed above you will need to whitelist the hosts dormammu.lookback.io  and *.dormammu.lookback.io   (sometimes referred to as the common-name) in your firewall configuration. Our clients will attempt to fall back to port 443  when connecting to these hosts in the event other ports are inaccessible.

  • Wildcard whitelisting
    If your firewall does not support wildcard whitelisting such as *.dormammu.lookback.io  your IT team can write code to poll https://live.production.lokb.net/registry/hosts on a regular basis (e.g. once every 10 minutes) to get a list of active servers to whitelist.

  • Web sockets
    Lookback uses Web Sockets, as detailed here, to provide realtime functions such as instantly showing when participants arrive and communicating during live sessions. Lookback does not function properly without Web Sockets.

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