kernel2.4.18_&_ipchains

В ядрах 2.4+ используются стандартно ip_tables. Однако если нужны именно ip_chains смотри в разделе networking что-то про совместимость со старыми версиями

#
#   IP: Netfilter Configuration
#
CONFIG_IP_NF_CONNTRACK=m
CONFIG_IP_NF_FTP=m
CONFIG_IP_NF_IRC=m
# CONFIG_IP_NF_QUEUE is not set
CONFIG_IP_NF_IPTABLES=m
# CONFIG_IP_NF_MATCH_LIMIT is not set
# CONFIG_IP_NF_MATCH_MAC is not set
# CONFIG_IP_NF_MATCH_MARK is not set
# CONFIG_IP_NF_MATCH_MULTIPORT is not set
# CONFIG_IP_NF_MATCH_TOS is not set
# CONFIG_IP_NF_MATCH_AH_ESP is not set
# CONFIG_IP_NF_MATCH_LENGTH is not set
# CONFIG_IP_NF_MATCH_TTL is not set
# CONFIG_IP_NF_MATCH_TCPMSS is not set
# CONFIG_IP_NF_MATCH_STATE is not set
# CONFIG_IP_NF_MATCH_UNCLEAN is not set
# CONFIG_IP_NF_MATCH_OWNER is not set
CONFIG_IP_NF_FILTER=m
CONFIG_IP_NF_TARGET_REJECT=m
CONFIG_IP_NF_TARGET_MIRROR=m
CONFIG_IP_NF_NAT=m
CONFIG_IP_NF_NAT_NEEDED=y
CONFIG_IP_NF_TARGET_MASQUERADE=m
CONFIG_IP_NF_TARGET_REDIRECT=m
# CONFIG_IP_NF_NAT_SNMP_BASIC is not set
CONFIG_IP_NF_NAT_IRC=m
CONFIG_IP_NF_NAT_FTP=m
CONFIG_IP_NF_MANGLE=m
# CONFIG_IP_NF_TARGET_TOS is not set
# CONFIG_IP_NF_TARGET_MARK is not set
# CONFIG_IP_NF_TARGET_LOG is not set
# CONFIG_IP_NF_TARGET_ULOG is not set
# CONFIG_IP_NF_TARGET_TCPMSS is not set
CONFIG_IP_NF_COMPAT_IPCHAINS=y
CONFIG_IP_NF_NAT_NEEDED=y
CONFIG_IPV6=m