Red Hat Enterprise Linux 5 Administration Unleashed

496CHAPTER 24Configuring a FirewallECNWork around for known ECN blackholes. Only valid with the mangle table.--ecn-tcp-removeRemove all ENC bits from the TCP header. Only valid with -p tcp.IPMARKMark a received packet based on its IP. Should be used in the mangle table with thePREROUTING, POSTROUTING, or FORWARD chains.--addr Source or destination IP address.--and-mask AND the IP and defined mask.--or-mask OR the IP and defined mask.IPV4OPTSSTRIPStrip IP options from packet.LOGEnable kernel logging for matching packets. Logs go to dmesg or syslog.--log-level Log level specified as a number or the syslog log level name.--log-prefix Define a prefix for the log messages up to 29 letters.--log-tcp-sequenceLog TCP sequence numbers.--log-tcp-optionsLog options from the TCP packet header.--log-ip-optionsLog options from the IP packet header.--log-uidLog UID of the process that generated the packet.MARKSet netfilter mark value for packet. Only valid with mangle table.--set-mark Define mark to use.