SNMP_TRAP_PORT 172 net/ipv4/netfilter/nf_nat_snmp_basic_main.c if (udph->dest == htons(SNMP_TRAP_PORT) && dir != IP_CT_DIR_ORIGINAL) SNMP_TRAP_PORT 211 net/ipv4/netfilter/nf_nat_snmp_basic_main.c .tuple.src.u.udp.port = cpu_to_be16(SNMP_TRAP_PORT),