[OZAPRS] Ozaprs Digest, Vol 8, Issue 25

Mark Aitken vk3jma at yahoo.com.au
Sat Apr 29 15:18:46 EST 2006


Hello,

I think you will find that this is just a network broadcast, possibly 
something line Netbios or Samba anouncing
it's self to the network  Windows does the same from time to time.  the
hint 
is the dest IP address,

192.168.1.255,  any money you have a netmask of something like 
255.255.255.0, hence the 192.168.1 being a constant
and the 255 being the network broadcast address.  This means that any
system 
in your network with the same netmask will
respond to that 255 frame however if a frames was sent onto the network
with 
a dest ip of say 192.168.255.255 your system would
ignore this, it's netmask would be, 255.255.0.0.  this way, you can
segment 
a lan into different subnets and there will be no iteraction
between the two unless there was a gateway system that did Network 
Translation (NAT) or similar.

eg  ip address of 192.168.0.1 Netmask of 255.255.255.240 would allow a 
system to have 14 ip addresses it would respond to directly,
  .0 through to .13  the network broadcast in this case would be 
192.168.0.13  (I maybe wrong with the limits, this is all from memory)

      ip address of 192.168.0.14 netmask 255.255.255.240 would allow a 
system to have 14 ip addresses it would respond to directly,
  .14 through to .28  the network broadcast in this case would be 
192.168.0.28

These two subnets would then allow to totally seperate "lans" to operate
on 
the same physical carrier, be it cat5, RF, optic fibre etc.

Network administrators use this method to keep the various dept's of a 
company seperate while utilising the same cables.

So to simpily answer your question, it's normal TCP/IP activity you are 
wittnessing.

> VK1HCT-1>QST>UI,?
>  IP: UDP, Source: 192.168.1.1, Dest: 192.168.1.255, Len: 252
> VK1HCT-1>QST>UI,?,CC
>  IP: UDP, Source: 192.168.1.1, Dest: 192.168.1.255, Len: 33
> VK1HCT-1>QST>UI,?,CC
>  IP: UDP, Source: 192.168.1.1, Dest: 192.168.1.255, Len: 235
>
> 192.168.1.1 being the IP number I have assigned to AX0 port. It looks to
> me like some process is either pinging the port or sending a beacon. At
> this point APRSD isn't running.
>
> Any suggestions for where to start looking? I want to be able to leave
the
> station on 24hrs a day, but at the moment I don't want it to congest the
> network with these packets.
>
> 

Send instant messages to your online friends http://au.messenger.yahoo.com

_______________________________________________
Ozaprs mailing list
Ozaprs at aprs.net.au
http://aprs.net.au/mailman/listinfo/ozaprs



More information about the Ozaprs mailing list