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DHCP datagram?

Discussion in 'Tomato Firmware' started by clarkman, Mar 12, 2010.

  1. clarkman

    clarkman Addicted to LI Member

    Hey all;

    I'm new here, so by way of brief introduction let me say thanks to polarcloud for this wonderful tool!! We use it in remote science stations, often with funky satellite data links and ISPs in strange lands! And it has been wonderful.

    We've been with tomato since 23, and we use hi-gain Yagi antennas and a NAT port forwarding to allow login in to our site, which is often hundreds of meters from the nearest structure. Thanks to tomato's tools, we have virtually eliminated problems with the wireless part of our system (that were formerly killing us!)

    Anyways, sorry if this is here already somewhere, but now we must tackle another problem (opportunity for fun!). Tomato is configured for DHCP on the WAN side, but we must know the address in order to log in!! So we have devised a system where our site LAN computer extracts the WAN address from the router via ssh command (thank you for that!). The site computer then includes the IP address in the very small UDP heartbeat datagram that we send out every five seconds from every site. Not the best design, but it works.

    Now it has become clear that we need something more solid. I'd like to add a simple UDP broadcaster to Tomato that sends a separate UDP datagram sans our LAN site computer, so that in the event that the wireless or site computer goes down, we can still get the router WAN address to log in and troubleshoot (unless any of you have a better idea). So before I go and port a UDP sender to the tomato code base, it occurs to me that many have had this need, and to ask you about it before I re-invent the wheel!

    Thanks for your time and attention -

  2. clarkman

    clarkman Addicted to LI Member

    Oh, why don't we just read the IP address out of the recvfrom() call on this end? Because the satellite ISPs substitute another IP for the real one - :mad:. Only our DSL links give us the correct IP address out of the receiving socket!!

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