[AG-TECH] multicast TALE OF WOE

Sun Sep 7 14:15:16 CDT 2003

First thing you should check is that your firewall accepts ALL traffic (
well UDP should be enough)  on class D network (multicast range)
You can see very often that by default firewalls drop all incoming 
traffic ( including multicast) but allow everything out.
That would explain why others can see you.
Hope that helps.
Grzesiek 
On Thu, 2003-09-04 at 23:02, Stephen Bosch wrote:
> Hi, everybody:
> 
> Okay -- I admit, this multicast stuff is Hungarian to me. I've installed 
> mtrace, the kernel is configured for multicast, I'm supposed to be on a 
> multicast-enabled network, but when I run the NLANR beacon, it looks 
> like other sites can see me, but I am receiving nothing from them; this 
> is clearly not a beacon problem, as AccessGrid stuff is not working 
> either. At Todd Zimmerman's advice I tried to connect directly to 
> NewMIC's venue, but got nothing.
> 
> I've included some diagnostic output below to help in identifying the 
> problem:
> 
> root at accessgrid:/usr/src/linux-2.4.20# mtrace beaconserver.accessgrid.org
> mtrace: WARNING: no multicast group specified, so no statistics printed
> Mtrace from 140.221.9.160 to 206.75.91.40 via group 0.0.0.0
> Querying full reverse path... * switching to hop-by-hop:
>    0  accessgrid.netera.ca (206.75.91.40)
>   -1  host206-75-91-33.netera.ca (206.75.91.33)  PIM/BGP4+  thresh^ 0
>   -2  * * * c4-van01.canet4.net (205.189.32.198)  PIM  thresh^ 1
>   -3  * * c4-win01.canet4.net (205.189.32.2)  PIM  thresh^ 1
>   -4  * * c4-mren.canet4.net (205.189.32.69)  PIM/BGP4+  thresh^ 0
>   -5  * * anl-mren-gige.anchor.anl.gov (192.5.170.213)  PIM  thresh^ 0
>   -6  * * stardust-guava.anchor.anl.gov (130.202.222.73)  PIM  thresh^ 0
>   -7  ag-tech.mcs.anl.gov (140.221.9.160)
> Round trip time 80 ms; total ttl of 6 required.
> 
> COMMENT Seems to work only as far as our router.
> 
> root at accessgrid:~# mtrace beaconserver.accessgrid.org 206.75.91.40 
> 233.2.171.1
> Mtrace from 140.221.9.160 to 206.75.91.40 via group 233.2.171.1
> Querying full reverse path...
>    0  accessgrid.netera.ca (206.75.91.40)
>   -1  host206-75-91-33.netera.ca (206.75.91.33)  PIM  thresh^ 0  Reached 
> RP/Core
> Round trip time 1 ms; total ttl of 1 required.
> 
> Waiting to accumulate statistics...Results after 10 seconds:
> 
>    Source        Response Dest    Overall     Packet Statistics For 
> Traffic From
>     * * *        224.0.1.32       Packet      140.221.9.160 To 233.2.171.1
>       v       __/  rtt    1 ms     Rate       Lost/Sent = Pct  Rate
> 206.75.91.33    host206-75-91-33.netera.ca Reached RP/Core
>       v      \__   ttl    2         0 pps        ?/0            0 pps
> 206.75.91.40    206.75.91.40
>    Receiver      Query Source
> 
> COMMENT: We are not receiving anything :)
> 
> root at accessgrid:~# mtrace ag.triumf.ca 206.75.91.40 233.2.171.1
> Mtrace from 142.90.97.14 to 206.75.91.40 via group 233.2.171.1
> Querying full reverse path...
>    0  accessgrid.netera.ca (206.75.91.40)
>   -1  host206-75-91-33.netera.ca (206.75.91.33)  PIM  thresh^ 0  Reached 
> RP/Core
> Round trip time 1 ms; total ttl of 1 required.
> 
> Waiting to accumulate statistics...Results after 10 seconds:
> 
>    Source        Response Dest    Overall     Packet Statistics For 
> Traffic From
>     * * *        224.0.1.32       Packet      142.90.97.14 To 233.2.171.1
>       v       __/  rtt    1 ms     Rate       Lost/Sent = Pct  Rate
> 206.75.91.33    host206-75-91-33.netera.ca Reached RP/Core
>       v      \__   ttl    2         0 pps        ?/0            0 pps
> 206.75.91.40    206.75.91.40
>    Receiver      Query Source
> 
> root at accessgrid:~# mtrace cluster.vislab.usyd.edu.au 206.75.91.40 
> 233.2.171.1
> Mtrace from 129.78.157.79 to 206.75.91.40 via group 233.2.171.1
> Querying full reverse path...
>    0  accessgrid.netera.ca (206.75.91.40)
>   -1  host206-75-91-33.netera.ca (206.75.91.33)  PIM  thresh^ 0  Reached 
> RP/Core
> Round trip time 1 ms; total ttl of 1 required.
> 
> Waiting to accumulate statistics...Results after 10 seconds:
> 
>    Source        Response Dest    Overall     Packet Statistics For 
> Traffic From
>     * * *        224.0.1.32       Packet      129.78.157.79 To 233.2.171.1
>       v       __/  rtt    1 ms     Rate       Lost/Sent = Pct  Rate
> 206.75.91.33    host206-75-91-33.netera.ca Reached RP/Core
>       v      \__   ttl    2         0 pps        ?/0            0 pps
> 206.75.91.40    206.75.91.40
>    Receiver      Query Source
> 
> eth1      Link encap:Ethernet  HWaddr 00:07:E9:18:CA:CA
>            inet addr:206.75.91.40  Bcast:206.75.91.47 Mask:255.255.255.240
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            RX packets:167845 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:1656033 errors:389 dropped:0 overruns:0 carrier:389
>            collisions:57357 txqueuelen:100
>            RX bytes:229841872 (219.1 Mb)  TX bytes:177592616 (169.3 Mb)
>            Interrupt:19 Base address:0x2080 Memory:e8120000-e8140000
> 
> 
> root at accessgrid:~# route
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use 
> Iface
> 206.75.91.32    *               255.255.255.240 U     0      0        0 eth1
> 206.75.91.0     *               255.255.255.0   U     0      0        0 eth1
> localnet        *               255.255.255.0   U     0      0        0 eth0
> loopback        *               255.0.0.0       U     0      0        0 lo
> 224.0.0.0       *               240.0.0.0       U     0      0        0 eth1
> default         host136-159-94- 0.0.0.0         UG    0      0        0 eth0
> 
> 
> Anything here that looks suspicious? Note -- we get these results even 
> when our non-multicast interface is disabled.
> 
> So -- is the problem on our machine, or is it a multicast routing problem?
> 
> Thanks for any help you can provide.
> 
> -Stephen-
-- 
Grzesiek Sedek <grzesiek at mi2.hr>