port forward vps's public ipv4 addr to private ipv4 addr via IPIP6 tunnel

NETMAPで IP アドレスを 1:1でNATしていたのが前回ですが、今回はもう少し進んでみて、Port forwardの設定をしてみました。構成は以下の通りです。

それでは早速設定です。前回と異なるところだけですが、まずはVPS側のvyosのnatの設定は以下の通りです。

set nat destination rule 10 destination address '10.10.10.1'
set nat destination rule 10 destination port '80'
set nat destination rule 10 inbound-interface 'eth0'
set nat destination rule 10 protocol 'tcp'
set nat destination rule 10 translation address '192.168.10.125'
set nat destination rule 10 translation port '80'

set nat destination rule 11 destination address '10.10.10.1'
set nat destination rule 11 destination port '443'
set nat destination rule 11 inbound-interface 'eth0'
set nat destination rule 11 protocol 'tcp'
set nat destination rule 11 translation address '192.168.10.125'
set nat destination rule 11 translation port '443'

set nat destination rule 12 destination address '10.10.10.1'
set nat destination rule 12 destination port '53'
set nat destination rule 12 inbound-interface 'eth0'
set nat destination rule 12 protocol 'tcp'
set nat destination rule 12 translation address '192.168.10.126'
set nat destination rule 12 translation port '53'

set nat destination rule 13 destination address '10.10.10.1'
set nat destination rule 13 destination port '53'
set nat destination rule 13 inbound-interface 'eth0'
set nat destination rule 13 protocol 'udp'
set nat destination rule 13 translation address '192.168.10.126'
set nat destination rule 13 translation port '53'

set nat source rule 10 outbound-interface 'eth0'
set nat source rule 10 protocol 'tcp'
set nat source rule 10 source address '192.168.10.125'
set nat source rule 10 source port '80'
set nat source rule 10 translation address '10.10.10.1'
set nat source rule 10 translation port '80'

set nat source rule 11 outbound-interface 'eth0'
set nat source rule 11 protocol 'tcp'
set nat source rule 11 source address '192.168.10.125'
set nat source rule 11 source port '443'
set nat source rule 11 translation address '10.10.10.1'
set nat source rule 11 translation port '443'

set nat source rule 12 outbound-interface 'eth0'
set nat source rule 12 protocol 'tcp'
set nat source rule 12 source address '192.168.10.126'
set nat source rule 12 source port '53'
set nat source rule 12 translation address '10.10.10.1'
set nat source rule 12 translation port '53'

set nat source rule 13 outbound-interface 'eth0'
set nat source rule 13 protocol 'udp'
set nat source rule 13 source address '192.168.10.126'
set nat source rule 13 source port '53'
set nat source rule 13 translation address '10.10.10.1'
set nat source rule 13 translation port '53'

set protocols static route 192.168.10.0/24 next-hop 172.16.2.2

VPS側のvyosのnatの設定は以上です。これでパブリックアドレスへの80,443,53のアクセスは、図の通りのポート・アドレスに転送されます。
なお、vps側のvyosのiptables(nat)の部分は以下のようになります。

*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:VYATTA_PRE_DNAT_HOOK - [0:0]
:VYATTA_PRE_SNAT_HOOK - [0:0]
-A PREROUTING -j VYATTA_PRE_DNAT_HOOK
-A PREROUTING -d 10.10.10.1/32 -i eth0 -p tcp -m tcp --dport 80 -m comment --comment DST-NAT-10 -j DNAT --to-destination 192.168.10.125:80
-A PREROUTING -d 10.10.10.1/32 -i eth0 -p tcp -m tcp --dport 443 -m comment --comment DST-NAT-11 -j DNAT --to-destination 192.168.10.125:443
-A PREROUTING -d 10.10.10.1/32 -i eth0 -p tcp -m tcp --dport 53 -m comment --comment DST-NAT-12 -j DNAT --to-destination 192.168.10.126:53
-A PREROUTING -d 10.10.10.1/32 -i eth0 -p udp -m udp --dport 53 -m comment --comment DST-NAT-12 -j DNAT --to-destination 192.168.10.126:53

-A POSTROUTING -j VYATTA_PRE_SNAT_HOOK
-A POSTROUTING -s 192.168.10.125/32 -o eth0 -p tcp -m tcp --sport 80 -m comment --comment SRC-NAT-10 -j SNAT --to-source 10.10.10.1:80
-A POSTROUTING -s 192.168.10.125/32 -o eth0 -p tcp -m tcp --sport 443 -m comment --comment SRC-NAT-11 -j SNAT --to-source 10.10.10.1:443
-A POSTROUTING -s 192.168.10.126/32 -o eth0 -p tcp -m tcp --sport 53 -m comment --comment SRC-NAT-12 -j SNAT --to-source 10.10.10.1:53
-A POSTROUTING -s 192.168.10.126/32 -o eth0 -p udp -m udp --sport 53 -m comment --comment SRC-NAT-12 -j SNAT --to-source 10.10.10.1:53

-A VYATTA_PRE_DNAT_HOOK -j RETURN
-A VYATTA_PRE_SNAT_HOOK -j RETURN
COMMIT
# Completed on Wed Apr  1 05:21:35 2020

続いて、ローカル側のDebian routerで注意すべきなのは、太線を見ればわかるように、ローカル側のDebianルータのserver1, server2 に対するゲートウェイはInternet router側ではなく、VPS側トンネル先である172.16.2.1にすることです。そのほかのデフォルトルートはInternet Router(192.168.1.1)経由となります。具体的には以下のようになります。

#/etc/network/interfaces.d/eth0
auto eth0
iface eth0 inet static
  address 192.168.1.124
  netmask 255.255.255.0
  gateway 192.168.1.1
  nameservers 8.8.8.8 1.1.1.1
iface eth0 inet6 static
  address 2400:XXXX:YYYY:ZZZZ:AAAA:BBBB:CCCC:2
  netmask 56
  up ip -6 route add default via fe80::1 dev eth0

#/etc/network/interfaces.d/tun0
auto tun0
iface tun0 inet tunnel
  mode ipip6
  address 172.16.2.2
  netmask 255.255.255.0
  local    2400:XXXX:YYYY:ZZZZ:AAAA:BBBB:CCCC:2
  endpoint 2400:AAAA:BBBB:CCCC:XXXX:YYYY:ZZZZ:1
  up ip route add default via 172.16.2.1 dev tun0 tab 99
  up ip rule add from 192.168.10.125 sport 80  table 99 prio 99
  up ip rule add from 192.168.10.125 sport 443 table 99 prio 99
  up ip rule add from 192.168.10.126 sport 53  table 99 prio 99

前回のNETMAP設定もそうですが、トンネル経由のPort Forwardの設定もネットでは見かけなかったので、本稿をアップしてみました。今回は以上です。ではまた。