Hi, I am trying to set up a uPnP server on a Linux box (Debian Sarge Stable kernel 2.6.8). uPnP works using multicast packages for locating servers. This does however seem to fail unless I set the relevant NIC in promiscuous mode. If I do so, it works well. I have added ip route add 224.0.0.0/4 dev eth0 and echo 1 >/proc/sys/net/ipv4/ip_forward and the kernel is set up to enable multicast (and routing), extract from the .config of the kernel: # # Networking options # CONFIG_PACKET=y CONFIG_PACKET_MMAP=y # CONFIG_NETLINK_DEV is not set CONFIG_UNIX=y CONFIG_NET_KEY=y CONFIG_INET=y CONFIG_IP_MULTICAST=y CONFIG_IP_ADVANCED_ROUTER=y CONFIG_IP_MULTIPLE_TABLES=y CONFIG_IP_ROUTE_FWMARK=y CONFIG_IP_ROUTE_NAT=y CONFIG_IP_ROUTE_MULTIPATH=y CONFIG_IP_ROUTE_TOS=y CONFIG_IP_ROUTE_VERBOSE=y # CONFIG_IP_PNP is not set CONFIG_NET_IPIP=y CONFIG_NET_IPGRE=y CONFIG_NET_IPGRE_BROADCAST=y CONFIG_IP_MROUTE=y CONFIG_IP_PIMSM_V1=y CONFIG_IP_PIMSM_V2=y # CONFIG_ARPD is not set CONFIG_SYN_COOKIES=y CONFIG_INET_AH=y CONFIG_INET_ESP=y CONFIG_INET_IPCOMP=y The server is also used as a firewall using iptables and iproute2 and thus also serves as a gateway for the uPnP clients. Something is missing, and I do not want the NIC to be in promiscuous mode permanently if it can be avioded. What do I do wrong? Regards Henrik