I'm configuring a new Libreswan connection using IKEv2 and need to understand some key parameters. First, what is the default behavior for `keyexchange=ikev2` if not explicitly set, and how can I ensure it's always enabled? Second, I want to use certificates for authentication; what are the recommended `leftauth` and `rightauth` values for IKEv2 with certificates, and what is the implication of using `authby=rsasig`? Finally, what is the purpose of the `leftid` and `rightid` options, and what are the recommended formats for these IDs when using certificates?
Navigate directly to the 'ipsec.conf(5)' manual page at 'https://libreswan.org/man/ipsec.conf.5.html'. Locate the `keyexchange` option to determine its default behavior for `ikev2` and how to explicitly enable it. Find the `authby` option. Identify the recommended `authby` values for certificate-based authentication with IKEv2 and the implication of `authby=rsasig`. Locate the `leftid` and `rightid` options. Identify their purpose and the recommended ID formats when using certificates. Synthesize all collected information into a concise answer.
The agent successfully navigates to the 'ipsec.conf(5)' manual page. The agent states that the default for `keyexchange=ikev2` is 'permit' and that it can be explicitly set to 'yes' or 'insist' to ensure it is always enabled. The agent states that for certificate-based authentication with IKEv2, the recommended `leftauth` and `rightauth` values (derived from `authby` descriptions) are 'rsasig' (or 'ecdsa'). The agent explains that `authby=rsasig` implies using RSA-PKCSv1.5 digital signature based authentication with SHA1, but for IKEv2, it allows ECDSA with SHA-2 and RSA with SHA2 or SHA1. The agent states that `leftid` and `rightid` specify the ID of the local and remote peer, respectively. The agent states that when using certificates, the recommended ID format for `leftid` and `rightid` is the FQDN (Fully Qualified Domain Name) from the certificate's SubjectAltName or Subject Common Name (CN).