Someone forget to add ipt_ah files? :)
--- linux.orig/net/ipv4/netfilter/Makefile Tue Oct 30 23:08:12 2001
+++ linux/net/ipv4/netfilter/Makefile Wed Jan 23 20:24:37 2002
@@ -56,6 +56,7 @@
obj-$(CONFIG_IP_NF_MATCH_MULTIPORT) += ipt_multiport.o
obj-$(CONFIG_IP_NF_MATCH_OWNER) += ipt_owner.o
obj-$(CONFIG_IP_NF_MATCH_TOS) += ipt_tos.o
+obj-$(CONFIG_IP_NF_MATCH_AH_ESP) += ipt_ah.o ipt_esp.o
ld: cannot open ipt_ah.o: No such file or directory
make[3]: *** [netfilter.o] Error 1
make[3]: Leaving directory `/usr/local/src/linux/net/ipv4/netfilter'
-d