We received new Firepower 4100 series hardware, we are able to access Management IP via GUI but we are unable to access FTD via GUI, ping is possible.
Could you please let me how know to access FTD ? via https or to access FTD we need FMC as mandatory
The "FTD GUI" (local) is known as Firepower Device Manager (FDM). It is not available for FTD on 4100 or 9300 series appliances.
As @mikael.lahtela noted, you need to run Firepower Management Center (FMC) on a separate server.
Wait, FDM's still only on 2100, not 4100/9300? But you can't manage FTD from an FMC that's on the outside of your firewall, and I thought CDO-with-FDM was the most likely support direction for next year?
FDM is not currently available for FTD on 4100 or 9300 series. This is confirmed in Table 1 here:
You can manage FTD from and FMC that is outside your firewall. There are at least two ways:
1. Easiest is to put the management interface on the public subnet. The communications to and from FMC is TLS-encrypted over tcp/8305 so it's no less secure than CDO using the API over TLS to the cloud.
2. Second method is to pre-configure the appliance on premises and register to the FMC and then deploy it to the remote site. The traffic can flow from management interface via inside interface and then over site-site IPsec VPN (if you want to keep all private addressing and further protect the confidentiality of the data) or be NATted and reach the remote FMC which you have assigned a public IP with restrictions on the inbound communications on the firewall at that end.