I have an issue using certs as well, though I am not 100% sure whether it has to do with a CA cert chain (why did you come to this conclusion?). Do you have a config and a debug trace to share?
--- Igor V. Gubenko System Engineer On 2018-02-21 20:14, Stuart Henderson wrote: > Has anyone already figured out how to, or know whether it's possible > to, get iked working with letsencrypt certs? (Or indeed any CA with > chain certs?) > > Use case: "standard" clients (Windows/iOS/StrongSwan), EAP auth, > not particularly technical users so trying to avoid the need for them > to manually install certs. > > Most of it should be straightforward (at least for FQDN), the server > cert has SAN, I think the main issue seems to be due to the chain cert. > > If I place only the "CN=Let's Encrypt Authority X3" in iked/ca/ca.crt > iked doesn't startup properly ("unable to get issuer certificate" for my > own cert and "unable to get local issuer certificate" for the LE CA). > > If I place only the "DST Root CA X3" in ca.crt I get "did not find > subjectAltName" and "no valid local certificate found". > > If I place both ca and chain certs in ca.crt it looks like it starts > up ok: > > ca_reload: loaded ca file ca.crt > ca_reload: loaded crl file ca.crl > ca_reload: /O=Digital Signature Trust Co./CN=DST Root CA X3 > ca_reload: /C=US/O=Let's Encrypt/CN=Let's Encrypt Authority X3 > ca_reload: loaded 2 ca certificates > ca_reload: loaded cert file blahblahblah.com.crt > > but then actually connecting fails (at least from strongswan, I need to > dig out the other test devices again..).