Client Request DHCP another interface

[nhimcoi30889]

Hi eveybody,
I have a problem as:
My Pfsense has 3 NICs card.
  - NIC 1: Use for WAN connection
  - NIC 2: Use for LAN connection ( DHCP range 10.220.2.10-200/24) <–-------------- Dont use Wifi devices
  - NIC 3: Use for Wifi connection ( DHCP range 172.18.0.10-172.18.7.254/16) <---------- Only use for Wifi devices

Sometime client (mobile) connect to wifi, but it request to LAN DHCP and alert wrong network. then it request to DHCP Wifi
Detail log

Feb 22 16:11:02 dhcpd DHCPREQUEST for 172.18.4.79 from ec:35:86:19:0e:xx (Owners-iPhone) via em2: wrong network.
Feb 22 16:11:02 dhcpd DHCPNAK on 172.18.4.79 to ec:35:86:19:0e:xx via em2
Feb 22 16:11:04 dhcpd DHCPREQUEST for 10.220.2.210 from ec:35:86:19:0e:xx via em2
Feb 22 16:11:04 dhcpd DHCPACK on 10.220.2.210 to ec:35:86:19:0e:89 (Owners-iPhone) via em2

[jimp]

Clients will typically request the address they had before when connecting to a network. It doesn't mean there is a problem, since they will get rejected and then send a new request to get a new address. It's a common behavior for DHCP clients to want to keep the same address if possible.

Now if they actually obtained an address for the wrong network, then you might have some cause to worry since it means you have an L2 connection between the segments so they're actually on the same switch segment which isn't what you want. That doesn't appear to be the case from what little you've shown in the log at least.