IPSEC VPN to client with Dynamic IP Address

[ADW]

Hi All,
I'm fairly new to pfSense, so apologies if this has been covered before.
I'm attempting to set up an IPSEC VPN between my pfSense firewall which is on a fixed IP address & a client's Netgear DG834 router which is on a dynamic address, but has a DynamicDNS domain name that remains constant.  I've set up both sides with the same IKE parameters & PSK, but the tunnel won't come up & I'm getting the racoon error "racoon: ERROR: Expecting IP address type in main mode, but FQDN." in the pfSense IPSEC log.  Having read through a few other posts, am I right in thinking that using a FQDN for either end of the VPN tunnel requires the use of Agressive mode & isn't supported when using Main mode.  As the Netgear DG834 only supports Main mode, what are my options for getting a working VPN.

TIA, ADW