Strongswan zu strongswan ikev2 site to site

Config is the same on both sites

ipsec.conf

Erklärung

• ipsec.conf Erklärung

Datei

conn s2s
     authby=secret
     keyexchange=ikev2
     left=10.82.227.12
     leftid=10.82.227.12
     leftsubnet=10.82.243.0/24
     mobike=no
     right=10.82.227.22
     rightid=10.82.227.22
     rightsubnet=10.82.244.0/24
     ike=aes256-sha256-modp4096!
     esp=aes256-sha256-modp4096!
     auto=start

ipsec.secrets

ID Kombination mit Authentifizierungsmethodes

10.82.227.12 10.82.227.22  : PSK "suxer"

Up

• ipsec up s2s

initiating IKE_SA s2s[2] to 10.82.227.22
generating IKE_SA_INIT request 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(HASH_ALG) N(REDIR_SUP) ]
sending packet: from 10.82.227.12[500] to 10.82.227.22[500] (720 bytes)
received packet: from 10.82.227.22[500] to 10.82.227.12[500] (728 bytes)
parsed IKE_SA_INIT response 0 [ SA KE No N(NATD_S_IP) N(NATD_D_IP) N(FRAG_SUP) N(HASH_ALG) N(CHDLESS_SUP) N(MULT_AUTH) ]
selected proposal: IKE:AES_CBC_256/HMAC_SHA2_256_128/PRF_HMAC_SHA2_256/MODP_4096
authentication of '10.82.227.12' (myself) with pre-shared key
establishing CHILD_SA s2s{2}
generating IKE_AUTH request 1 [ IDi N(INIT_CONTACT) IDr AUTH SA TSi TSr N(MULT_AUTH) N(EAP_ONLY) N(MSG_ID_SYN_SUP) ]
sending packet: from 10.82.227.12[500] to 10.82.227.22[500] (256 bytes)
received packet: from 10.82.227.22[500] to 10.82.227.12[500] (224 bytes)
parsed IKE_AUTH response 1 [ IDr AUTH SA TSi TSr N(AUTH_LFT) ]
authentication of '10.82.227.22' with pre-shared key successful
IKE_SA s2s[2] established between 10.82.227.12[10.82.227.12]...10.82.227.22[10.82.227.22]
scheduling reauthentication in 10119s
maximum IKE_SA lifetime 10659s
selected proposal: ESP:AES_CBC_256/HMAC_SHA2_256_128/NO_EXT_SEQ
CHILD_SA s2s{2} established with SPIs cc16cb02_i c89d755d_o and TS 10.82.243.0/24 === 10.82.244.0/24
connection 's2s' established successfully

Down

• ipsec down s2s

deleting IKE_SA s2s[2] between 10.82.227.12[10.82.227.12]...10.82.227.22[10.82.227.22]
sending DELETE for IKE_SA s2s[2]
generating INFORMATIONAL request 2 [ D ]
sending packet: from 10.82.227.12[500] to 10.82.227.22[500] (80 bytes)
received packet: from 10.82.227.22[500] to 10.82.227.12[500] (80 bytes)
parsed INFORMATIONAL response 2 [ ]
IKE_SA deleted
IKE_SA [2] closed successfully

Status

• ipsec status s2s

Security Associations (1 up, 0 connecting):
         s2s[4]: ESTABLISHED 7 seconds ago, 10.82.227.12[10.82.227.12]...10.82.227.22[10.82.227.22]
         s2s{4}:  INSTALLED, TUNNEL, reqid 1, ESP SPIs: cef198fc_i c4de821a_o
         s2s{4}:   10.82.243.0/24 === 10.82.244.0/24

TCPDump der Verbindung

• tcpdump -ni eth0 port 500 or esp

up

tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
listening on eth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes
09:03:46.060570 IP 10.82.227.12.500 > 10.82.227.22.500: isakmp: parent_sa ikev2_init[I]
09:03:46.173147 IP 10.82.227.22.500 > 10.82.227.12.500: isakmp: parent_sa ikev2_init[R]
09:03:46.230911 IP 10.82.227.12.500 > 10.82.227.22.500: isakmp: child_sa  ikev2_auth[I]
09:03:46.234449 IP 10.82.227.22.500 > 10.82.227.12.500: isakmp: child_sa  ikev2_auth[R]

down

09:04:02.224802 IP 10.82.227.12.500 > 10.82.227.22.500: isakmp: child_sa  inf2[I]
09:04:02.228834 IP 10.82.227.22.500 > 10.82.227.12.500: isakmp: child_sa  inf2[R]

Mehrere Subnetze

alice und tiazel

• /etc/ipsec.conf

conn s2s
     authby=secret
     keyexchange=ikev2
     left=10.82.227.12
     leftid=10.82.227.12
     leftsubnet=10.82.243.0/24,192.168.20.0/24
     mobike=no
     right=10.82.227.22
     rightid=10.82.227.22
     rightsubnet=10.82.244.0/24
     ike=aes256-sha256-modp4096!
     esp=aes256-sha256-modp4096!
     auto=start

• ipsec status

Security Associations (1 up, 0 connecting):
         s2s[2]: ESTABLISHED 5 seconds ago, 10.82.227.12[10.82.227.12]...10.82.227.22[10.82.227.22]
         s2s{2}:  INSTALLED, TUNNEL, reqid 1, ESP SPIs: cda686f1_i c7f9fce6_o
         s2s{2}:   10.82.243.0/24 192.168.20.0/24 === 10.82.244.0/24

Links

• https://www.heise.de/security/artikel/Einfacher-VPN-Tunnelbau-dank-IKEv2-270056.html