Mozilla officials have refused a US government request to ban a Firefox add-on that helps people to access sites that use internet domain names confiscated in an unprecedented seizure earlier this year.

The request came from officials at the Immigration and Customs Enforcement, the agency under the Department of Homeland Security that in February took the unprecedented step of seizing domain names accused of streaming live pay-per-view sporting events. Without giving the owners an opportunity to defend themselves, ICE officials obtained a court order that gave them control of the addresses, which ended in .com, .net, and .org.

That's where MafiaaFire came in. The Firefox add-on, available on Mozilla.org, made it easy for users to access sites that used some of the confiscated addresses. It did this by redirecting them to substitute domain names that were out of the reach of US courts, such as those with a .de top level domain.

“You simply type Demoniod.com into your browser as usual,” the add-on's authors wrote in an FAQ explaining how it works. “The browser sends the address to the add-on, the add-on checks if Demoniod.com is on the list of sites to be redirected and immediately redirects you to the mirror site.

According to a blog post published on Thursday by Mozilla General Counsel Harvey Anderson, ICE officials alleged MafiaaFire circumvented their seizure order and asked Mozilla to remove it.

The open-source group, in not so many words, said no.

“Our approach is to comply with valid court orders, warrants, and legal mandates, but in this case there was no such court order,” Anderson explained.

He continued: “The problem stems from the use of these government powers in service of private content holders when it can have unintended and harmful consequences. Longterm, the challenge is to find better mechanisms that provide both real due process and transparency without infringing upon developer and user freedoms traditionally associated with the internet.”

Indeed, a vocal chorus of lawmakers and policy wonks have decried the domain seizures, arguing that the ex parte actions are a serious power grab that threaten the stability of the internet. If the US government can confiscate addresses it doesn't agree with, what's to stop China or any other country from doing the same thing?

So far, at least 92 domain names have been seized under the program, which ICE officials have dubbed Operation in our Sites. Two of the affected domain names are rojadirecta.org and rojadirecta.com, which belong to a site that was recently ruled to be operating legally in Spain, where it is headquartered.

Anderson said he responded to the ICE request by sending officials a set of detailed questions that among other things asked: “What protections are in place for MAFIAAfire.com or the seized domain owners if eventually a court decides they were not unlawful?”

So far, he's received no response. ®