doc: Update description of Phase2-keyword

diff --git a/doc/config-format.txt b/doc/config-format.txt
index f86f3f7..f3c8f01 100644 (file)
--- a/doc/config-format.txt
+++ b/doc/config-format.txt
@@ -39,7 +39,9 @@ This is for private keys generated by using their own filesystem UUID as the
 passphrase. The PrivateKeyPassphrase field is ignored when this field is set
 to fsid.
 - Identity: Identity string for EAP.
-- Phase2: Phase2 (inner authentication with TLS tunnel) parameters.
+- Phase2: Phase2 (inner authentication with TLS tunnel) authentication method.
+Prefix the value with "EAP-" to indicate the usage of an EAP-based inner
+authentication method (should only be used with EAP = TTLS).
 - Passphrase: RSN/WPA/WPA2 Passphrase