Multicast over NAT

[Travis H.]

> I found that I need to allow packets with allow-opts (IGMP) - which I
> also tried, but it doesn`t help... If i trie to fetch playlist in VLC
> via SAP announces, it sends some IGMP packets to $int_if, but they won`t
> pass out on $ext_if. Is it possible to config Packet Filter to support
> multicast traffic.

IGMP is its own protocol, like TCP or UDP.  You need to create a rule
that allows it.  Also you will likely need to create rules for the
appropriate multicast addresses; I don't think that referring to an
interface will pick up the multicast addresses (it doesn't pick up
subnet-directed broadcast or local broadcast).

Beyond that, I don't know.  I've never fooled with IGMP... if all else
fails, consider reading the RFC.
--
http://www.lightconsulting.com/~travis/  -><- Knight of the Lambda Calculus
"We already have enough fast, insecure systems." -- Schneier & Ferguson
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