Pulling this off requires high privileges in the network, so if this is done by intruder you’re probably having a Really Bad Day anyway, but might be good to know if you’re connecting to untrusted networks (public wifi etc). For now, if you need to be sure, either tether to Android - since the Android stack doesn’t implement DHCP option 121 or run VPN in VM that isn’t bridged.
Yes, it could attempt ARP attacks too, though I’m not sure how that would affect DHCP traffic, since it’s broadcast, not routed. I haven’t had to work that angle.
(Also, “implicitive” should just be “implicit”; it’s already an adjective.)
I was going for “implicated”, but suffered a critical failure in my word formation attempt.
(Still better than that one time when I decided that past tense of “to bug [someone]” was “buggered”)