Student or Learner
dear all in theses sentences
1)the rogue server could
send a carefully crafted DHCP reply with its own IP address substituted as the default gateway
i haven't understand crafted
it recognizes that all packets destined off-net
must be sent to the gateway’s MAC address rather than the far end’s MAC address
i haven't understand off-net
thank you all
"crafted" means "made" or "written" or "designed" - usually implies by hand. In a normal usage, something is hand-crafted, or machine-made.
"off-net" I believe means not on the Internet; that is, it resides in a particular computer, or perhaps within a local network. This one is jargon; that is, it is a specialized language that is younger than me.