Apologies in advance if this is a stupid question. I have just started exploring network designs and firewalls.
I have come across a network design where there is single firewall between internet, DMZ and the internal network.
From my understanding, DMZ works best if at least two firewalls are utilised in a network design; one as the perimeter firewall and the other as internal firewall. Why would someone design the network with DMZ with just one firewall? Is there a significant benefit (or risks) by designing the network as such?
I have also read that the use of DMZ is to make intrusions to the internal network more difficult. So the servers/services sitting in the DMZ zone is not important? Or are they just some kind of bait/honyepot or are they just supposed to be expendable assets? I am confused with this because I have seen web servers and FTP servers sitting there. Does it mean they are not important servers??