Messages in this thread | | | From | "Matthew Delco" <> | Subject | ISSUE: Linux bug/restriction prevents multicast participation | Date | Thu, 14 Sep 2000 00:40:01 -0700 |
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Bug report form (as suggested by the old mailing list FAQ) ----------------------------------------------------------
Summary: A bug/misguided restriction in Linux prevents users from participating in certain multicast video sessions.
Full description: Multicast standards prescribe that the port range 49152-65535 be used for video traffic. From my observations, Linux does not allow user processes to use multicast sessions with ports 61000+, and therefore Linux can not participate in many multicast video sessions. Since unicast sockets can't bind to the port range either, I'm assuming that this port range was reserved with some purpose in mind (IP masquerading?), but regardless this restriction is being inappropriately applied to the class-D multicast range.
Keywords: networking, kernel, multicast
Kernel version: 2.2.16-3 (and others)
Environment (example): Kernel modules 2.3.10-pre1 Gnu C egcs-2.91.66 Binutils 2.9.5.0.22 Linux C Library 1.3.so Linux C++ Library 2.7.2.8.so Procps 2.0.6 Mount 2.10f Net-tools (1999-04-20) Kbd [option...] Sh-utils 2.0 Sh-utils Parker. Sh-utils Sh-utils Inc. Sh-utils NO Sh-utils PURPOSE.
Example trigger of problem: use any classic multicast app to join a session that utilizes a port in the restricted range.
Other notes, patches, fixes, workarounds: No external solution is available, since sessions are announced using automated tools (SDR) on various OSes, and it's unreasonable to force users to recompile and run a hacked kernel to use multicast or run programs such as vic/vat as setuid root (assuming there's a way for root to get around this restriction, which I'm not sure is possible).
I've already mentioned this problem in other forums (both physical and electronic), and basically received no informed responses.
Thanks,
MD
http://mash.cs.berkeley.edu/ http://www.openmash.org/ http://bmrc.berkeley.edu/
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