无法在 strongswan 和 AWS VPN 网关之间设置站点到站点 vpn 连接

Question

I have been trying to setup a site to site vpn connection between aws and my on-prem network. We have a dedicated strongswan vpn gateway in our on-prem network and aws managed vpn gateway on the aws side. Whatever I do I am unable to setup the tunnel. Here is my strongswan config.

conn Tunnel1
    type=tunnel
    auto=add
    keyexchange=ikev2
    authby=psk
    leftid=<Outside-tunnel-ip>
    leftsubnet=<AWS CIDR>
    right=<Outside-tunnel-ip>
    rightsubnet=<ON-PREM CIDR>
    aggressive=no
    ikelifetime=28800s
    lifetime=3600s
    margintime=270s
    rekey=yes
    rekeyfuzz=100%
    fragmentation=yes
    replay_window=1024
    dpddelay=30s
    dpdtimeout=120s
    dpdaction=restart
    ike=aes256-sha256-modp2048!
    esp=aes256-sha256-modp2048!
    keyingtries=%forever
    mark=100
    leftupdown="/etc/ipsec.d/aws-updown.sh -ln Tunnel1 -ll <tunnel inside ip> -lr <tunnel outside ip>  -m 100 -r <aws_vpc_id>"

I have made sure the configuration I have on aws side matches with configuration on strongswan side. But I still can't establish the tunnel.

Logs from strongswan daemon.

ipsec[164912]: Starting strongSwan 5.9.5 IPsec [starter]...
charon: 00[DMN] Starting IKE charon daemon (strongSwan 5.9.5, Linux 5.15.0-1004-aws, x86_64)
charon: 00[LIB] providers loaded by OpenSSL: legacy default
charon: 00[CFG] loading ca certificates from '/etc/ipsec.d/cacerts'
charon: 00[CFG] loading aa certificates from '/etc/ipsec.d/aacerts'
charon: 00[CFG] loading ocsp signer certificates from '/etc/ipsec.d/ocspcerts'
charon: 00[CFG] loading attribute certificates from '/etc/ipsec.d/acerts'
charon: 00[CFG] loading crls from '/etc/ipsec.d/crls'
00[CFG] loading secrets from '/etc/ipsec.secrets'
charon: 00[CFG]   loaded IKE secret for <outside tunnel ip left> <outside tunnel ip right>
charon: 00[LIB] loaded plugins: charon aesni aes rc2 sha2 sha1 md5 mgf1 random nonce x509 revocation constraints pubkey pkcs1 pkcs7 pkcs8 pkcs12 pgp dnskey sshkey pem openssl fips-prf gmp agent xcbc hmac gcm drbg attr kernel-netlink resolve socket-default connmark stroke updown eap-mschapv2 xauth-generic counters
charon: 00[LIB] dropped capabilities, running as uid 0, gid 0
charon: 00[JOB] spawning 16 worker threads
ipsec[164912]: charon (164916) started after 20 ms
charon: 05[CFG] received stroke: add connection 'Tunnel1'
charon: 05[CFG] added configuration 'Tunnel1'

Answer 1

Make sure you have the rightsubnet=<AWS_internal_network> and left_subnet=<AWS_internal_network>

On libreswan I also added: leftsourceip=<CGW_internal_ip> rightsourceip=<VGW_internal_ip>