[Spread-users] UDP broadcast question

Jonathan Stanton jonathan at cnds.jhu.edu
Wed Apr 16 18:48:38 EDT 2003

On Tue, Apr 15, 2003 at 03:29:39PM -0500, Monte Ohrt wrote:
> Hello,
> We use currently use spread (v. 3.16.02) and mod_log_spread and
> spreadlogd to send apache logs from a web cluster to a log server. Our
> spread.conf file looks like this:
> Spread_Segment {
> server1
> server2
> server3
> (etc)
> }

Is your network mask really a class B (/16) network space? Using a
broadcast address of is sending the packets to all of the
machines in the 10.131.*.* address space which is probably not what you
want :-)

If your networks broadcast address is actually then
changing to that will help some. You can also switch to using a
Multicast address as long as all the machines using spread are on the
same lan segment and your OS supports IP-multicast (most modern ones

If you switch to multicast, replace the with 225.131.x.y
(you can pick almost any network address between and, but some of the 224.* ones are reserved). Then the
traffic will be filtered to only those machines who are part of the
spread configuration.

> I notice by all the blinking lights on the switch that the packets are
> being broadcast across the entire network segment. We only have one
> server ( doing the chore of listening and logging the
> spread messages with spreadlogd. Is it possible to have the packets

Is this machine running a daemon? I don't think so since it's ip address
is not in the config file. If it is just a client connecting to adaemon
on another machine, then the config file doesn't affect it at all. 

> directed to that machine only (still via UDP) instead of broadcasted? If
> so, how do I accomplish this? I thought about changing the configuration
> to this:

No. This won't work. The segment address does need to be a broadcast or
multicast address so all the servers can communicate on it, even if you
only have one "listener"



Jonathan R. Stanton         jonathan at cs.jhu.edu
Dept. of Computer Science   
Johns Hopkins University    

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