Tue Jul 22 22:24:43 PDT 2003
So Prismiq released a "preview release" of their Linux media server, so I purchased one of their machines. The machine is OK, but after an awful lot of debugging on the linux server I discovered that their server detection mechanism basically consists of the server dumping UDP packets to a seemingly meaningless address 239.251.255.255 at a fairly good rate (At least 1 a second). Apparently these packets are detected by the prismiq client which can then identify the sender from the header.
This mechanism seems like a bad idea for several reasons.
- Constantly dropping packets on your network seems like a inefficient waste
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of resources. 2. These packets are routable to someplace, currently mine are headed for the
WAN. This is really bad for me since they go out the wrong ethernet
interface, so the client never sees them. 3. Some poor network out there is getting a lot of UDP packets.
Anyway, hopefully the prismiq developers will respond with a simpler solution than the current idea that I have which is to add a routing rule to dump the UDP packets onto my local interface instead of going out to the WAN. But I’m a bit hesitant to add another rule, as I’m not that good at writing these rules and I’m concerned that it might have some strange side effects…
We also tried flying the kite again yesterday, but the wind was still too variable. We are going to have to go to the coast to get any steady wind.
Tue Jul 29 23:18:27 PDT 2003
UPDATE: Turns out that the UDP packets are multicast packets. So adding a rule to support multicast routing to my /etc/rc.d/rc.local to route them:
sbin/ip route add 224.0.0.0/4 dev eth0
Was the necessary trick :-)