[Udpcast] Problems with udpcast 20051223

John Newbigin jnewbigin at ict.swin.edu.au
Mon Feb 13 01:17:43 CET 2006


Alain Knaff wrote:

> John Newbigin wrote:
> 
I checked all the interfaces and they are configured correctly.
inet addr:136.186.5.90  Bcast:136.186.5.255  Mask:255.255.255.0

I am using ethernet bonding on some of the machines so that might be a 
possible issue.  I also have a firewall enabled on the sender.  I am 
running RHEL2.1AS (CentOS-2) which is the 2.4 linux kernel.  I don't 
have multicast routes in the routing tables.  I tried adding them but 
that did not help.

I ran tcpdump and I see igmp traffic and traffic on udp 9000 but I don't 
know exactly what I am looking for.  Does someone have a tcpdump log 
from a working setup?

John.

> 
>> and none of the clients work.
> 
> 
> This is more surprising. I just did a test here with 2 receivers (_before_
> fixing the compilation error and the double connect message issue), and
> everything worked just fine.
> 
> Are you sure your network interfaces are set up correctly? (For a single
> receiver, udpcast uses unicast, but for multiple receivers it uses
> broadcast or multicast, so if for whatever reason broadcast and/or
> multicast does not work on your net, there may be problems). One
> possible problem area could be if the net is configured for a different
> broadcast address on the sender than on the receiver(s). Do an ifconfig
> to check this out:
> 
> 
>> ifconfig eth0
> 
> eth0      Link encap:Ethernet  HWaddr 00:04:61:45:6B:1C
>           inet addr:192.168.1.10  Bcast:192.168.1.255  Mask:255.255.255.0
>                                         ^^^^^^^^^^^^^
>                                               |
>  [This address should be the same for all machines on your network]
> 
>           inet6 addr: fe80::204:61ff:fe45:6b1c/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:389 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:449 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:1000
>           RX bytes:131658 (128.5 Kb)  TX bytes:182962 (178.6 Kb)
>           Interrupt:12 Base address:0xe400
> 
> 
> 
> 
> Try doing a tcpdump while doing both tests.
> 
> Also, make sure that you see (on the sender) connect messages for both
> receivers:
> 
> New connection from 192.168.1.3  (#0) 00000009
> Ready. Press any key to start sending data.
> New connection from 192.168.1.2  (#1) 00000009
> Ready. Press any key to start sending data.
> 
>> I have also tested netcast (http://sourceforge.net/projects/netcast) 
>> which works with multiple clients so I don't think it is a multicast 
>> issue.  netcast does not have many features so I would like to use 
>> udpcast.
>>
>> I have also got the message
>> Unexpected opcode 0700
>> and
>> Unexpected opcode 0200
>> a few times so I wonder if that is related to my problem.
> 
> 
> Actually, it's not related. Udp-receiver was sending its connection
> message twice, but the sender is able to deal with it (and just resends
> its reply). At that point, the receiver no longer expects the reply, so
> it just ignores it (... and displayes the message).
> 
> In any case, I've uploaded a new tar (udpcast-20060208.tar.gz) which
> fixes both the compilation and the double connect message issue (but
> as said: multiple receivers do also work without these fixes... so the
> reason for your multiple receivers problem must lie somewhere else...)
> 
>> Any help would be greatly appreciated.
>>
>> John.
>>
>>
> 
> 
> Regards,
> 
> Alain
> 
> 
> 


-- 
John Newbigin
Computer Systems Officer
Faculty of Information and Communication Technologies
Swinburne University of Technology
Melbourne, Australia
http://www.ict.swin.edu.au/staff/jnewbigin




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