IPv6 Enkripsi: Contoh IPsec Tunnel Menggunakan racoon

Pada kesempatan ini akan di berikan contoh untuk membuat Ipsec tunnel menggunakan racoon pada dua gateway Linux berbasis sistem operasi Ubuntu 18.04.

Gateway A: IPv6 2345::100/64	LAN Network: 2002::/64
Gateway B: IPv6 2345::101/64	LAN Network: 2003::/64

Topology Jaringan

LAN A ------- GW A ------------ GW B ----------- LAN B
2002::/64     2345::100/64      2345::101/64     2003::/64

GW A

enp0s3 2345::100/64
enp0s8 2002::1/64

GW B

enp0s3 2345::101/64
enp0s8 2003::1/64

Konfigurasi interface

GW A

ip address add 2345::100/64 dev enp0s3
ip address add 2002::1/64 dev enp0s8

GW B

ip address add 2345::101/64 dev enp0s3
ip address add 2003::1/64 dev enp0s8

Kernel IP Forwarding

Pada Gateway A dan Gateway B, kita perlu mengaktifkan kernel IP forwarding ,

echo 1 > /proc/sys/net/ipv4/conf/all/forwarding
echo 1 > /proc/sys/net/ipv6/conf/all/forwarding

atau edit

vi /etc/sysctl.conf

net.ipv6.conf.all.forwarding=1
net.ipv6.conf.default.forwarding=1
net.ipv6.conf.enp0s3.forwarding=1
net.ipv6.conf.enp0s8.forwarding=1
net.ipv6.conf.tun0.forwarding=1

Seharusnya cukup all.forwarding=1 saja. Save dan jalankan di shell

sysctl -p

Instalasi racoon dan ipsec-tools

Pada Gateway A dan Gateway B, instalasi:

apt update
apt install racoon ipsec-tools 

Pada pertanyaan “Configuration mode for racoon IKE daemon:” jawab “direct”

Konfigurasi racoon

Konfigurasi Gateway A

Gateway A Konfigurasi /etc/racoon/racoon.conf

log notify; 
path pre_shared_key "/etc/racoon/psk.txt"; 
remote 2345::101 { 
        exchange_mode main,aggressive; 
        proposal { 
                encryption_algorithm 3des; 
                hash_algorithm sha1; 
                authentication_method pre_shared_key; 
                dh_group 2; 
        } 
} 

sainfo address 2002::/64 any address 2003::/64 any { 
        pfs_group 2; 
        lifetime time 1 hour ; 
        encryption_algorithm 3des, blowfish 448, rijndael ; 
        authentication_algorithm hmac_sha1, hmac_md5 ; 
        compression_algorithm deflate ; 
} 

Gateway A Konfigurasi /etc/racoon/psk.txt

2345::101 a9993e364706816aba3e 

Konfigurasi Gateway B

Gateway B Konfigurasi /etc/racoon/racoon.conf

log notify; 
path pre_shared_key "/etc/racoon/psk.txt"; 
remote 2345::100 { 
        exchange_mode main,aggressive; 
        proposal { 
                encryption_algorithm 3des; 
                hash_algorithm sha1; 
                authentication_method pre_shared_key; 
                dh_group 2; 
        } 
} 

sainfo address 2003::/64 any address 2002::/64 any { 
        pfs_group 2; 
        lifetime time 1 hour ; 
        encryption_algorithm 3des, blowfish 448, rijndael ; 
        authentication_algorithm hmac_sha1, hmac_md5 ; 
        compression_algorithm deflate ; 
} 

Gateway B Konfigurasi /etc/racoon/psk.txt

2345::100  a9993e364706816aba3e 

Security Policies

Konfigurasi Gateway A

Gateway A Konfigurasi /etc/ipsec-tools.conf

flush; 
spdflush; 
spdadd 2002::/64 2003::/64 any -P out ipsec 
           esp/tunnel/2345::100-2345::101/require; 
spdadd 2003::/64 2002::/64 any -P in ipsec 
           esp/tunnel/2345::101-2345::100/require; 

Konfigurasi Gateway B

Gateway B Konfigurasi /etc/ipsec-tools.conf

flush; 
spdflush; 
spdadd 2003::/64 2002::/64 any -P out ipsec 
           esp/tunnel/2345::101-2345::100/require;
spdadd 2002::/64 2003::/64 any -P in ipsec 
           esp/tunnel/2345::100-2345::101/require; 

Run

Di Gateway A dan Gateway B jalankan,

/etc/init.d/setkey restart 
/etc/init.d/racoon restart 

Akan tampak

[ ok ] Restarting setkey (via systemctl): setkey.service.
[ ok ] Restarting racoon (via systemctl): racoon.service.

Cek /var/log/syslog

Jalankan

tail /var/log/syslog

Akan keluar kira-kira

Feb 19 06:18:34 minimalis setkey[2555]:  * Loading IPsec SA/SP database:
Feb 19 06:18:34 minimalis setkey[2555]:    ...done.
Feb 19 06:18:34 minimalis systemd[1]: Stopping ipsec key exchange server...
Feb 19 06:18:35 minimalis systemd[1]: Stopped ipsec key exchange server.
Feb 19 06:18:35 minimalis systemd[1]: Starting ipsec key exchange server...
Feb 19 06:18:35 minimalis racoon: INFO: @(#)ipsec-tools 0.8.2 (http://ipsec-tools.sourceforge.net)
Feb 19 06:18:35 minimalis racoon: INFO: @(#)This product linked OpenSSL 1.0.2n  7 Dec 2017 (http://www.openssl.org/)
Feb 19 06:18:35 minimalis racoon: INFO: Reading configuration from "/etc/racoon/racoon.conf"
Feb 19 06:18:35 minimalis systemd[1]: racoon.service: Can't open PID file /var/run/racoon.pid (yet?) after start: No such file or directory
Feb 19 06:18:35 minimalis systemd[1]: Started ipsec key exchange server.

Pastikan tidak ada error. Jika ada error timeout, restart ipsec dan racoon.

Tambahkan Routing

Pada Gateway A tambahkan routing

ip -6 addr add 2002::1/64 dev enp0s8
ip -6 route add to 2003::/64 dev enp0s3

Pada Gateway B tambahkan routing

ip -6 addr add 2003::1/64 dev enp0s8
ip -6 route add to 2002::/64 dev enp0s3

Setelah VPN tersambung, coba dari Gateway A:

ping6 2003::1

Lakukan penyadapan wireshark antara GW A dan GW B, harusnya packet di enkapsulasi menggunakan ESP.

Debugging

Sebaiknya simulasi di jalankan menggunakan GNS3. Proses debugging bisa menggunakan fasilitas untuk sniffing yang built-in di GNS3.

Dari mesin Gateway B 2345::101 Proses debugging jika dibutuhkan dapat menggunakan tcpdump dengan perintah, misalnya,

#  tcpdump -t -n -i eth0 -vv ip6 host 2345::100

atau menggunakan wireshark.

Pranala Menarik

• IPv6