Cloudflare filed to go public on Thursday, and it listed its controversial former clients in the risk factors section of its filing.

Cloudflare, a web protection service, once served a neo-Nazi website and 8chan, an online forum connected to three deadly mass shootings.

Though Cloudflare ultimately terminated its client relationships with both sites, the company said that its past association with the customers, and its subsequent responses, have the potential to pose adverse business consequences.

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Cybersecurity startup Cloudflare filed the paperwork for an IPO on Thursday with disclaimers about a couple of controversial former clients: a neo-Nazi, white supremacist website, and a notorious online forum connected to mass shootings.

Cloudflare offers content delivery network, or CDN, services. One purpose of a CDN is to protect websites against attacks like a Distributed Denial of Service cyberattack, which can disable a website by flooding and overwhelming it with traffic. Cloudflare also speeds up content delivery.

In its S-1 filing, Cloudflare addressed the negative press it received as a result of its former customers The Daily Stormer and 8chan. Then, the company specified that activities of its customers have alienated potential clients before: "We are aware of some potential customers that have indicated their decision to not subscribe to our products was impacted, at least in part, by the actions of certain of our paying and free customers."

"We experienced significant negative publicity in connection with the use of our network by The Daily Stormer, a neo-Nazi, white supremacist website, around the time of the 2017 protests in Charlottesville, Virginia," the filing reads. "We also received negative publicity in connection with the use of our network by 8chan, a forum website that served as inspiration for the recent attacks in El Paso, Texas and Christchurch, New Zealand."

Cloudflare terminated the The Daily Stormer in August 2017 following the white nationalist march "Unite the Right" in Charlottesville, Virginia, which left one counter-protester, Heather D. Heyer, dead. The Daily Stormer promoted the march, and a post on the site after the march read "We are going to go bigger than Charlottesville."

Cloudflare terminated 8chan in August 2019 after the mass shooting at a Walmart in El Paso, Texas, which left 22 people dead. CNN reported that the suspected shooters behind the El Paso attack, the Christchuch, New Zealand, mosque attack in March 2019, and the Poway, California, synagogue attack in April 2019 are all suspected of posting manifestos on 8chan.

"In the case of the El Paso shooting, the suspected terrorist gunman appears to have been inspired by the forum website known as 8chan," Prince wrote in a public termination notice posted on Cloudflare's website. "8chan has repeatedly proven itself to be a cesspool of hate," Prince continued.

Read more: The controversial company now protecting 8chan from online attacks also services an infamous neo-Nazi site

Clouldflare said in the IPO filing that its termination decisions also can negatively affect the company's reputation and brand.

"We received significant adverse feedback for these decisions from those concerned about our ability to pass judgment on our customers and the users of our platform, or to censor them by limiting their access to our products, and we are aware of potential customers who decided not to subscribe to our products because of this," the filing reads.

"At Cloudflare we believe in a free and open web" Prince wrote in a 2013 blog post on Cloudflare. "We do not believe that 'investigating' the speech that flows through our network is appropriate. In fact, we think doing so would be creepy."