var/nftables/filter.txt

   1 # A set containing the udp port(s) to which SSDP replies are allowed.
   2 set ssdp_out {
   3   type inet_service
   4   timeout 5s
   5 }
   6 set lograte4 { type ipv4_addr; size 65535; flags dynamic; }
   7 set lograte6 { type ipv6_addr; size 65535; flags dynamic; }
   8 chain block {
   9   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "block: "
  10   add @lograte6 { ip6 saddr limit rate 1/minute } log level warn prefix "block: "
  11   counter drop
  12 }
  13 chain ping-flood {
  14   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "ping-flood: "
  15   add @lograte6 { ip6 saddr limit rate 1/minute } log level warn prefix "ping-flood: "
  16   counter drop
  17 }
  18 chain smurf {
  19   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "smurf: "
  20   add @lograte6 { ip6 saddr limit rate 1/minute } log level warn prefix "smurf: "
  21   counter drop
  22 }
  23 chain bogus-tcp {
  24   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "bogus-tcp: "
  25   add @lograte6 { ip6 saddr limit rate 1/minute } log level warn prefix "bogus-tcp: "
  26   counter drop
  27 }
  28 chain syn-flood {
  29   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "syn-flood: "
  30   add @lograte6 { ip6 saddr limit rate 1/minute } log level warn prefix "syn-flood: "
  31   counter drop
  32 }
  33 chain check-tcp {
  34   tcp flags syn tcp option maxseg size != 536-65535 counter goto bogus-tcp
  35   tcp flags & (ack|fin) == fin counter goto bogus-tcp
  36   tcp flags & (ack|psh) == psh counter goto bogus-tcp
  37   tcp flags & (ack|urg) == urg counter goto bogus-tcp
  38   tcp flags & (fin|ack) == fin counter goto bogus-tcp
  39   tcp flags & (fin|rst) == (fin|rst) counter goto bogus-tcp
  40   tcp flags & (fin|psh|ack) == (fin|psh) counter goto bogus-tcp
  41   tcp flags & (syn|fin) == (syn|fin) counter goto bogus-tcp comment "SYN-FIN scan"
  42   tcp flags & (syn|rst) == (syn|rst) counter goto bogus-tcp comment "SYN-RST scan"
  43   tcp flags == (fin|syn|rst|psh|ack|urg) counter goto bogus-tcp comment "XMAS scan"
  44   tcp flags == 0x0 counter goto bogus-tcp comment "NULL scan"
  45   tcp flags == (fin|urg|psh) counter goto bogus-tcp
  46   tcp flags == (fin|urg|psh|syn) counter goto bogus-tcp comment "NMAP-ID"
  47   tcp flags == (fin|urg|syn|rst|ack) counter goto bogus-tcp
  48
  49   ct state new tcp flags != syn counter goto bogus-tcp
  50   tcp sport 0 tcp flags & (fin|syn|rst|ack) == syn counter goto bogus-tcp
  51   tcp flags & (fin|syn|rst|ack) == syn counter limit rate over 30/second burst 60 packets goto syn-flood
  52 }
  53 chain spoofing {
  54   add @lograte4 { ip  saddr limit rate 1/minute } log level warn prefix "spoofing: "
  55   counter drop
  56 }
  57 chain check-broadcast {
  58   #ip saddr 0.0.0.0/32 counter accept comment "DHCP broadcast"
  59   fib saddr type broadcast counter goto smurf
  60   #ip saddr 224.0.0.0/4     counter goto smurf
  61 }
  62 chain check-ping {
  63   ip protocol icmp icmp type echo-request limit rate over 10/second burst 20 packets goto ping-flood
  64   ip6 nexthdr ipv6-icmp icmpv6 type echo-request limit rate over 10/second burst 20 packets goto ping-flood
  65 }
  66 chain check-public {
  67   ip saddr 0.0.0.0/8 counter goto spoofing
  68   ip saddr 10.0.0.0/8 counter goto spoofing
  69   ip saddr 127.0.0.0/8 counter goto spoofing
  70   ip saddr 169.254.0.0/16 counter goto spoofing
  71   ip saddr 172.16.0.0/12 counter goto spoofing
  72   ip saddr 192.0.2.0/24 counter goto spoofing
  73   ip saddr 192.168.0.0/16 counter goto spoofing
  74   ip saddr 224.0.0.0/3 counter goto spoofing
  75   ip saddr 240.0.0.0/5 counter goto spoofing
  76 }
  77 chain accept-icmpv6 {
  78   # Traffic That Must Not Be Dropped
  79   # https://tools.ietf.org/html/rfc4890#section-4.4.1
  80   icmpv6 type destination-unreachable counter accept
  81   icmpv6 type packet-too-big counter accept
  82   icmpv6 type time-exceeded counter accept
  83   icmpv6 type parameter-problem counter accept
  84
  85   # Address Configuration and Router Selection messages
  86   # (must be received with hop limit = 255)
  87   icmpv6 type nd-router-solicit ip6 hoplimit 255 counter accept
  88   ip6 nexthdr ipv6-icmp icmpv6 type nd-router-advert ip6 hoplimit 255 counter accept
  89   icmpv6 type nd-neighbor-solicit ip6 hoplimit 255 counter accept
  90   icmpv6 type nd-neighbor-advert ip6 hoplimit 255 counter accept
  91   icmpv6 type nd-redirect ip6 hoplimit 255 log level warn prefix "icmpv6: nd-redirect: " counter drop
  92   icmpv6 type ind-neighbor-solicit ip6 hoplimit 255 counter accept
  93   icmpv6 type ind-neighbor-advert ip6 hoplimit 255 counter accept
  94
  95   # Link-local multicast receiver notification messages
  96   # (must have link-local source address)
  97   icmpv6 type mld-listener-query ip6 saddr fe80::/10 counter accept
  98   icmpv6 type mld-listener-report ip6 saddr fe80::/10 counter accept
  99   icmpv6 type mld-listener-done ip6 saddr fe80::/10 counter accept
 100   # https://tools.ietf.org/html/rfc3810 Multicast Listener Discovery Version 2 (MLDv2) for IPv6
 101   icmpv6 type mld2-listener-report ip6 saddr fe80::/10 counter accept
 102
 103   # SEND Certificate Path notification messages
 104   # (must be received with hop limit = 255)
 105   icmpv6 type 148 ip6 hoplimit 255 counter accept comment "certificate-path-solicitation"
 106   icmpv6 type 149 ip6 hoplimit 255 counter accept comment "certificate-path-advertisement"
 107
 108   # Multicast Router Discovery messages
 109   # (must have link-local source address and hop limit = 1)
 110   icmpv6 type 151 ip6 saddr fe80::/10 ip6 hoplimit 1 counter accept comment "multicast-router-advertisement"
 111   icmpv6 type 152 ip6 saddr fe80::/10 ip6 hoplimit 1 counter accept comment "multicast-router-solicitation"
 112   icmpv6 type 153 ip6 saddr fe80::/10 ip6 hoplimit 1 counter accept comment "multicast-router-termination"
 113 }
 114 chain accept-connectivity-input {
 115   # Connectivity checking messages
 116   # (multicast) ping
 117   ip protocol icmp icmp type echo-reply counter accept
 118
 119   # drop packets with rh0 headers
 120   rt type 0 jump block
 121   rt type 0 jump block
 122   rt type 0 jump block
 123
 124   # (multicast) ping
 125   ip6 nexthdr ipv6-icmp icmpv6 type echo-reply counter accept
 126   #ct state invalid counter drop
 127
 128   ip protocol icmp icmp type destination-unreachable counter accept
 129   ip protocol icmp icmp type time-exceeded counter accept
 130   ip protocol icmp icmp type parameter-problem counter accept
 131   ip protocol icmp icmp type echo-request limit rate over 10/second burst 20 packets goto ping-flood
 132   ip protocol icmp icmp type echo-request counter accept
 133   # echo-reply is handled before invalid packets to allow multicast ping
 134   # which do not have an associated connection.
 135
 136   ip6 nexthdr ipv6-icmp jump accept-icmpv6
 137
 138   # Connectivity checking messages
 139   icmpv6 type echo-request counter accept
 140   # echo-reply is handled before invalid because of multicast
 141 }
 142 chain accept-connectivity-output {
 143   ip protocol icmp counter accept
 144   meta skuid 0 udp dport 33434-33523 counter accept comment "traceroute"
 145
 146   ip6 nexthdr ipv6-icmp jump accept-icmpv6
 147
 148   # Connectivity checking messages
 149   ip6 nexthdr ipv6-icmp icmpv6 type echo-request counter accept
 150   ip6 nexthdr ipv6-icmp icmpv6 type echo-reply counter accept
 151 }
 152 chain accept-connectivity-forward {
 153   ip protocol icmp icmp type destination-unreachable counter accept
 154   ip protocol icmp icmp type time-exceeded counter accept
 155   ip protocol icmp icmp type parameter-problem counter accept
 156   ip protocol icmp icmp type echo-request counter accept
 157
 158   # Traffic That Must Not Be Dropped
 159   # https://tools.ietf.org/html/rfc4890#section-4.3.1
 160   ip6 nexthdr ipv6-icmp icmpv6 type destination-unreachable counter accept
 161   ip6 nexthdr ipv6-icmp icmpv6 type packet-too-big counter accept
 162   ip6 nexthdr ipv6-icmp icmpv6 type time-exceeded counter accept
 163   ip6 nexthdr ipv6-icmp icmpv6 type parameter-problem counter accept
 164
 165   # Connectivity checking messages
 166   ip6 nexthdr ipv6-icmp icmpv6 type echo-request counter accept
 167   ip6 nexthdr ipv6-icmp icmpv6 type echo-reply counter accept
 168
 169   # Traffic That Normally Should Not Be Dropped
 170   # https://tools.ietf.org/html/rfc4890#section-4.3.2
 171   ip6 nexthdr ipv6-icmp icmpv6 type 144 counter accept comment "home-agent-address-discovery-request"
 172   ip6 nexthdr ipv6-icmp icmpv6 type 145 counter accept comment "home-agent-address-discovery-reply"
 173   ip6 nexthdr ipv6-icmp icmpv6 type 146 counter accept comment "mobile-prefix-solicitation"
 174   ip6 nexthdr ipv6-icmp icmpv6 type 147 counter accept comment "mobile-prefix-advertisement"
 175 }