pfSense

Version 2.4.3-RELEASE (amd64)
built on Mon Mar 26 18:02:04 CDT 2018
FreeBSD 11.1-RELEASE-p7

I use the dchp server for my LAN. Any machine that connects by cable or wifi in the network automatically the dhcp server delivers in its range.
Available range 192.168.0.1 - 192.168.15.254

But for security initially assigned the range (192.168.15.2-192.168.15.254) the machine enters the network but does not surf the internet. For Security reasons.
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I leave the option STATIC ARP enabled because there the dhcp server relates IP + MAC of the card with the address with IP address (next I put the desired IP manually in order to be able to browse the Internet).
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When a new machine is inserted in the network we find its IP in the menu - Status -> DHCP Leases. That should be track 15.
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I'll go to Services-> DHCP Server-> LAN-> Edit Static Mapping- and add a new ip address in the range to browse and according to my error distribution. CASE I try to insert an IP address that is already in use presented the error message of IP already registered or MAC already registered or hostname also already registered. BUT after this last update it simply does not validate let duplicates items like IP, MAC or HOSTNAME. As a consequence the machine does not surf the internet.
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And there the problem in doubling IP
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I think it's a bug, this test is validated in my environment.