[Udpcast] udpcast receiver options

If I access a virtual console on the cast-o-matic PXE images I've generated, --rcvbuf is listed as a commandline option for udp-sender. The manpage for udp-sender suggests setting, "Try playing with the settings in /proc/sys/net/core/rmem_default and /proc/sys/net/core/rmem_max, i.e. setting them to a higher value" Does udp-receiver's "--rcvbuf" option modify rmem_default and/or rmem_max or some other value? -Tom C.