emails do not fail on domains with no mx records

[curibe]

Hello,

I notice that alot of emails stay in message queue that the recipient domain do not have a valid mx record. why isnt postfix noticing that there is no mx record for the recipient domain for that reason it should send a failure notification back to the user. lets say if i was to send an email to fdgajgfd@gmil.com (notice i typed gmail.com wrong) postfix should notice that gmil.com does not have an mx record so it should send failure notice to the sender.

is their a way to enable such settings in postfix?

[shawniverson]

It is, but the NDR response is much delayed...

5 days by default...

maximal_queue_lifetime = 5d