mulicast PIM-sparse and gre-tunnel through pix

[cwfun]

We want to implement Multicast through a PIX (6.6.3) between a 3550 and a 3750 . We have tested this in a lab where a session from internet->3550->pix->1760 worked well.(gre tunnel and PIX ok)Now in thelive network with a 3750 instead of the 1760 from the testlab I don't see any SPT tree with (S,G) on the inside side. We only want to use PIM sparse and can't upgrade yet to PIX 7.0 (then PIM is supported)

Anybody seen simmilar problems?

Any help would be appreciated

[ssoberlik]

this below document provides a sample configuration for multicasting over a generic routing encapsulation (GRE) tunnel.

http://www.cisco.com/en/US/tech/tk828/technologies_configuration_example09186a00801a5aa2.shtml