🚀 go-pugleaf

We are currently trying to configure a new router for our department and
have one last problem to be worked out.  The basic problem is that the
router does not seem to forward any multicast packets on test multicast
groups that we set up. 

For example:  I have two interfaces (Fast Ethernet), connected to 3Com
3300 switches.  Off of each of these, I have one host that is multicast capable
(one is Solaris, the other Linux).  On either, I can use SDR to create a
test multicast group.  I then can use either to be a source of traffic
for that group on the port number and address assigned.  The packets
make it to the router, the receiver sends its join message appropriately
and everything seems to be as it should.  A "show ip igmp group"
confirms that the receiver has joined.  A "show ip mpacket <group>"
shows that the router does indeed receive packets.  However, the
receiver never hears anything.  I've run tcpdump to confirm that no
packets in the multicast group are being forwarded to the other
interface.

Here are the relevant (?) settings for the router's config:

ip multicast-routing
ip multicast cache-headers
no ip dvmrp route-limit

interface FastEthernet4/0/0
 ip address x.x.x.x y.y.y.y
 ip pim sparse-dense-mode
interface FastEthernet4/1/0
 ip address w.w.w.w z.z.z.z
 ip pim sparse-dense-mode
interface FastEthernet5/0/0
 description Our link to the outside world and MBONE
 ip address a.a.a.a b.b.b.b
 ip pim sparse-dense-mode
 no ip route-cache optimum
 ip dvmrp unicast-routing

The unicast-routing is needed because we have two different links out to
the Internet at large.

Perhaps some useful info from when the tests are running (224.2.167.109
was the test multicast group address in this case):

#sho ip igmp groups
IGMP Connected Group Membership
Group Address    Interface            Uptime    Expires   Last Reporter
239.255.255.255  FastEthernet4/0/0    00:52:30  00:02:34  test source
239.255.255.255  FastEthernet5/0/0    5d03h     never     outside link
                                                          (a.a.a.a)
224.2.167.109    FastEthernet4/0/0    00:23:54  never     test source
224.2.167.109    FastEthernet4/1/0    00:41:07  never     test recv'r
224.2.127.253    FastEthernet4/0/0    00:52:32  00:02:32  test source
224.1.127.255    FastEthernet4/0/0    00:52:26  00:02:29  test source
224.2.127.254    FastEthernet4/0/0    00:52:32  00:02:32  test source
224.2.127.254    FastEthernet5/0/0    5d03h     never     outside link
224.2.255.116    FastEthernet4/0/0    00:52:29  00:02:25  test source
224.2.129.29     FastEthernet4/0/0    00:52:33  00:02:31  test source

#sho ip mroute 224.2.167.109

(*, 224.2.167.109), 01:56:18/00:00:00, RP 0.0.0.0, flags: DJCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    FastEthernet4/0/0, Forward/Sparse-Dense, 00:19:44/00:00:00
    FastEthernet4/1/0, Forward/Sparse-Dense, 00:36:58/00:00:00

#show ip mpacket 224.2.167.109
IP Multicast Header Cache - entry count: 1882, next index: 859
Key: id/ttl timestamp (name) source group

747C/1   446472.580 (test source) test-source-ip-addr 224.2.167.109
747D/1   446472.680 (test source) test-source-ip-addr 224.2.167.109
(many entries of this type)

#show ip igmp interfaces
FastEthernet4/0/0 is up, line protocol is up
  Internet address is x.x.x.x/yy
  IGMP is enabled on interface
  Current IGMP version is 2
  CGMP is disabled on interface
  IGMP query interval is 60 seconds
  IGMP querier timeout is 120 seconds
  IGMP max query response time is 10 seconds
  Inbound IGMP access group is not set
  IGMP activity: 8 joins, 2 leaves
  Multicast routing is enabled on interface
  Multicast TTL threshold is 0
  Multicast designated router (DR) is x.x.x.x (this system)
  IGMP querying router is x.x.x.x (this system)
  No multicast groups joined
FastEthernet4/1/0 is up, line protocol is up
  Internet address is w.w.w.w/zz
  IGMP is enabled on interface
  Current IGMP version is 2
  CGMP is disabled on interface
  IGMP query interval is 60 seconds
  IGMP querier timeout is 120 seconds
  IGMP max query response time is 10 seconds
  Inbound IGMP access group is not set
  IGMP activity: 3 joins, 2 leaves
  Multicast routing is enabled on interface
  Multicast TTL threshold is 0
  Multicast designated router (DR) is w.w.w.w (this system)
  IGMP querying router is w.w.w.w (this system)
  No multicast groups joined
FastEthernet5/0/0 is up, line protocol is up
  Internet address is a.a.a.a/bb
  IGMP is enabled on interface
  Current IGMP version is 2
  CGMP is disabled on interface
  IGMP query interval is 60 seconds
  IGMP querier timeout is 120 seconds
  IGMP max query response time is 10 seconds
  Inbound IGMP access group is not set
  IGMP activity: 3 joins, 1 leaves
  Multicast routing is enabled on interface
  Multicast TTL threshold is 0
  Multicast designated router (DR) is a.a.a.a (this system)
  IGMP querying router is router-on-other-end
  DVMRP unicast routing is enabled
  5 DVMRP routes + 0 poison-reverse routes received in last 00:00:26
  3/1 Unicast/DVMRP routes last advertised by DVMRP
  DVMRP output report delay is 100 ms, with burst size of 2
  Multicast groups joined: 224.2.127.254 239.255.255.255

Thanks,
Ethan

-- 

Ethan Haslett      UMass Computer Science Computing Facility  A313 LGRC
ethan@cs.umass.edu  (413)545-4296    FAX:(413)545-1249    
http://www.cs.umass.edu/~ethan/