Re: [lwip-users] FW: Problem by sending of UDP broadcast frame

[Dirk Ziegelmeier]

http://www.nongnu.org/lwip/2_0_x/upgrading.html

(2.0.0)

  ++ Application changes:

  * Changed netif "up" flag handling to be an administrative flag (as opposed to the previous meaning of
    "ip4-address-valid", a netif will now not be used for transmission if not up) -> even a DHCP netif
    has to be set "up" before starting the DHCP client

​This information could have also be obtained by simply stepping through your udp_sendto() until you reach the bottom of ip4_route() in a debugger.​