[Mailman-Users] How can I check if mailman is handling bounces correctly?

[Angel Gabriel]

How can I check if mailman is habdling bounces correctly? I have an
explicitly set return email address, so that anyone replying to the
mail, would send the mail to a monitored alias. But I also get a lot of
messages saying, undelivered mail etc. How does mailman know that these
messages are bouncing?? Or that these email addresses, are no good?
And how can I check that mailman knows this? About ten% of my list is
bouncing, and I would like to clean that up.