You don’t want to receive in the mail the IRS CP297 notice. This letter means that the IRS intends to levy your assets and seize your Passport because you have unpaid taxes and most likely have not responded to other attempts by the IRS to resolve your account. The notice will also tell you that you have the right to a hearing.
The IRS says your options are to pay what you owe or get into a payment plan. By the way, the IRS website mentions using an Offer In Compromise Program. We suggest you talk to a tax professional immediately about using the Offer In Compromise and Fresh Start Initiative options.