Eu tenho um roteador gentoo com duas instâncias openvpn (v2.4.6, udp e tcp) e a cada minuto eu sempre vejo essas mensagens de log:
Sep 12 15:42:50 lowpower2 openvpn[6505]: IP packet with unknown IP version=15 seen
Sep 12 15:42:50 lowpower2 openvpn[18725]: IP packet with unknown IP version=15 seen
Sep 12 15:43:51 lowpower2 openvpn[6505]: IP packet with unknown IP version=15 seen
Sep 12 15:43:51 lowpower2 openvpn[18725]: IP packet with unknown IP version=15 seen
Sep 12 15:44:53 lowpower2 openvpn[6505]: IP packet with unknown IP version=15 seen
Sep 12 15:44:53 lowpower2 openvpn[18725]: IP packet with unknown IP version=15 seen
Por exemplo, no lado do servidor tun1 (tcp), quando a vpn não está em uso, ou seja, nenhum cliente está conectado, com o tcpdump eu vejo isto:
lowpower2 ~ # tcpdump -n -X -i tun1
dropped privs to tcpdump
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tun1, link-type RAW (Raw IP), capture size 262144 bytes
15:37:42.981853 unknown ip 15
0x0000: ffff ffff ffff 0000 0000 0000 88a2 1000 ................
0x0010: ffff ff01 0000 0000 0000 0000 0000 0000 ................
15:38:44.421849 unknown ip 15
0x0000: ffff ffff ffff 0000 0000 0000 88a2 1000 ................
0x0010: ffff ff01 0000 0000 0000 0000 0000 0000 ................
15:39:45.861854 unknown ip 15
0x0000: ffff ffff ffff 0000 0000 0000 88a2 1000 ................
0x0010: ffff ff01 0000 0000 0000 0000 0000 0000 ................
Esta é a configuração do servidor para o udp
user nobody
group nobody
port 563
proto udp
multihome
dev tun0
persist-key
persist-tun
ca /etc/openvpn/server-multi/ca.crt
cert /etc/openvpn/server-multi/lowpower2.crt
key /etc/openvpn/server-multi/lowpower2.key
dh /etc/openvpn/server-multi/dh2048.pem
tls-auth /etc/openvpn/server-multi/ta.key 0
cipher AES-256-CBC
auth SHA512
ifconfig-pool-persist /etc/openvpn/server-udp-multi/ipp.txt
server 192.168.20.0 255.255.255.0
push "route 192.168.0.0 255.255.255.248"
push "route 192.168.11.0 255.255.255.0"
push "route 192.168.12.0 255.255.255.0"
push "route 192.168.13.0 255.255.255.0"
push "route 192.168.14.0 255.255.255.0"
keepalive 10 60
verb 3
max-clients 10
Esta é a configuração do servidor para tcp
user nobody
group nobody
port 1494
proto tcp-server
dev tun1
persist-key
persist-tun
ca /etc/openvpn/server-multi/ca.crt
cert /etc/openvpn/server-multi/lowpower2.crt
key /etc/openvpn/server-multi/lowpower2.key
dh /etc/openvpn/server-multi/dh2048.pem
tls-auth /etc/openvpn/server-multi/ta.key 0
cipher AES-256-CBC
auth SHA512
ifconfig-pool-persist /etc/openvpn/server-tcp-multi/ipp.txt
server 192.168.21.0 255.255.255.0
push "route 192.168.0.0 255.255.255.248"
push "route 192.168.1.0 255.255.255.0"
push "route 192.168.11.0 255.255.255.0"
push "route 192.168.12.0 255.255.255.0"
push "route 192.168.13.0 255.255.255.0"
push "route 192.168.14.0 255.255.255.0"
keepalive 10 60
verb 3
max-clients 10
Estes são os sinalizadores de uso:
Installed versions: 2.4.6(08:40:56 PM 09/11/2018)(iproute2 ssl -down-root -examples -inotify -libressl -lz4 -lzo -mbedtls -pam -pkcs11 -plugins -selinux -static -systemd -test KERNEL="linux" USERLAND="-BSD")
Este é o kernel:
Linux lowpower2 4.14.65-gentoo #3 SMP Thu Sep 6 22:05:43 CEST 2018 x86_64 Intel(R) Atom(TM) CPU D425 @ 1.80GHz GenuineIntel GNU/Linux
A que se deve? Que tipo de pacote é esse? É possível eliminar a mensagem de aviso sem diminuir o nível de detalhamento?