Here is a simple setup that I'm testing. The goal is the shape incoming NNTP traffic. Here is the script: tc qdisc del dev eth0 root 2>/dev/null tc qdisc add dev eth0 root handle 1:0 cbq bandwidth 10Mbit \ avpkt 1000 cell 8 tc class add dev eth0 parent 1:0 classid 1:100 cbq bandwidth 2Mbit \ rate 130Kbit prio 3 allot 1514 cell 8 maxburst 20 avpkt 1000 tc filter add dev eth0 parent 1:0 protocol ip prio 1 handle 1 \ fw classid 1:100 iptables -F -t mangle iptables -A PREROUTING -i eth0 -t mangle -p tcp --sport 119 \ -j MARK --set-mark 1 Here is the results of a simple test: # iptables -t mangle -L -v -n Chain PREROUTING (policy ACCEPT 220M packets, 107G bytes) pkts bytes target prot opt in out source destination 0 0 MARK tcp -- eth0 * 0.0.0.0/0 0.0.0.0/0 tcp spt:119 MARK set 0x1 Chain OUTPUT (policy ACCEPT 165M packets, 59G bytes) pkts bytes target prot opt in out source destination # telnet news.giganews.com 119 Trying 216.166.71.230... Connected to news-central.giganews.com. Escape character is '^]'. 200 News.GigaNews.Com (Typhoon v1.2.3) quit 205 GoodBye Connection closed by foreign host. # iptables -t mangle -L -vn Chain PREROUTING (policy ACCEPT 220M packets, 107G bytes) pkts bytes target prot opt in out source destination 6 377 MARK tcp -- eth0 * 0.0.0.0/0 0.0.0.0/0 tcp spt:119 MARK set 0x1 Chain OUTPUT (policy ACCEPT 165M packets, 59G bytes) pkts bytes target prot opt in out source destination # tc -s class show dev eth0 class cbq 1: root rate 10Mbit (bounded,isolated) prio no-transmit Sent 105328 bytes 1459 pkts (dropped 0, overlimits 0) borrowed 0 overactions 0 avgidle 624 undertime 0 class cbq 1:100 parent 1: rate 130Kbit prio 3 Sent 0 bytes 0 pkts (dropped 0, overlimits 0) borrowed 0 overactions 0 avgidle 1.30863e+06 undertime 0 # tc filter show dev eth0 filter parent 1: protocol ip pref 1 fw filter parent 1: protocol ip pref 1 fw handle 0x1 classid 1:100 Still no packets being filtered into my CBQ, but the packets are clearly being marked. -- Edwin Chiu | ICBM: 43.39N 79.23W edwin@xxxxxxxxxxxxxx | PGP: 1024D/0x16B55226