Parler, the social network popular with Trump supporters, is trickling back to life.

The social network went offline last week after Amazon booted it from its computer servers for not consistently removing violent posts, an accusation that Parler denied. But after a week in which Parler executives sued Amazon and predicted that their site might never return, they are forecasting it will be back up and running by the month’s end.

That turnabout is thanks, in part, to a Russian company.

Parler has entered into business with DDoS-Guard, a Russian firm that routes internet traffic and protects websites from cyberattacks. With its help, visitors to Parler.com now find a basic webpage with a promise from Parler’s chief executive, John Matze, that “our return is inevitable.”

But the use of a Russian company is worrying some researchers who study the internet and Russia. If Parler routes its web traffic through DDoS-Guard when its full website returns, the experts said, Russian law could enable the Russian government to surveil Parler’s users.

Alina Polyakova, head of the Center for European Policy Analysis, a foreign policy think tank in Washington, said Russia required many internet companies in the country to install technology that feeds the government a copy of much of the data that passes through their computer servers.

The surveillance system, known as the System for Operative Investigative Activities, “basically allows the Russian government to intercept any data on Russian territory and provide that data to the F.S.B.,” Russia’s domestic intelligence agency, said Ms. Polyakova, who has studied Russia’s control over the internet. She added that it was unclear if DDoS-Guard would be subject to such surveillance.

The Russian Embassy in Washington and DDoS-Guard did not respond to requests for comment. In an email to CNN, DDoS-Guard said it “does not provide any customer information or any other data to the government authorities, excluding cases explicitly stated in the law.”

Jeffrey Wernick, Parler’s chief operating officer, said in an interview that the concerns were overblown because DDoS-Guard supported only a temporary webpage for Parler. He said Parler would try to find other companies to operate its full social network.

“Our preference is to have an American firm,” he said. “People should not make conclusions that it’ll be this company. People extrapolate too much and with limited information. They conclude what they want to conclude. I call that spreading misinformation.”

But finding willing partners has been a challenge for Parler since the Capitol riot on Jan. 6.

After supporters of President Trump stormed the Capitol, Twitter and Facebook barred Mr. Trump from their services. That sent a flood of new people to Parler, pushing it past 15 million users. Then Apple and Google removed Parler’s app from their app stores and Amazon stopped hosting Parler’s website on its servers because, they said, Parler was not consistently removing violent posts. In addition to denying those claims, Parler accused the companies of collusion.

Since then, other companies have rebuffed Parler. Mr. Matze said in a court filing on Monday that “at least six extremely large potential providers” refused to take Parler’s business because they feared cyberattacks or believed Parler hosted incitements to violence.

“Parler is an internet company that cannot get on the internet,” Parler’s lawyer, David Groesbeck, said in a separate filing on Monday. “And the longer Parler lies dead, the harder it will be to resuscitate.”

Yet in statements to the press, Parler executives are predicting a full return by the end of January. Mr. Wernick declined to say how Parler would do that, but he attributed the confidence to a “herculean effort” by his team.

“We’re not sleeping,” he said. “We’re working day and night, and every day. There is no weekend for us.”

For Parler, the ideal solution would be returning to Amazon’s servers. The network has accused Amazon of violating antitrust law and asked a federal judge to force it to host Parler. After a hearing last week, the companies are now awaiting a ruling.

Many online observers and journalists have speculated that Parler will eventually be hosted by Epik, a company that has supported other websites that tech companies have rejected, including Gab, another social network popular in right-wing circles.

But Robert Davis, Epik’s senior vice president, said in an interview that Epik had only helped register Parler’s domain name, a basic function of the internet. While Epik would like to help, he said, Parler’s needs are too large.

“I would expect Parler to be an amazing force for good in the future,” he said. “I could see them easily hitting 100 million members or more in 2021 alone.”

Mr. Davis said he believed that Parler was trying to build its own infrastructure. On Monday, Mr. Matze appeared to support that notion in an interview on Fox News, saying, “We really need to build our own infrastructure and our own technology.”

In a legal filing on the same day, Mr. Matze said Parler did not have “the technical and security expertise to host the Parler environment on its own,” adding, “Nor is it feasible for Parler to do so.”

He said the computers and other equipment needed to host Parler’s site would cost more than $6 million and take weeks to arrive. “Simply put, it would not be possible for Parler itself to acquire the necessary servers and related security infrastructure in a commercially reasonable time frame,” he said.

Dave Temkin, an engineer who helped lead Netflix’s internet-infrastructure team until last week, said he was skeptical that Parler would return soon, given the difficulty of creating its own infrastructure and the reluctance of other companies to help.

He said that even if Parler built its own data center in the United States, it would need to persuade an internet provider like Verizon or AT&T to lay the fiber-optic cables to connect it to the wider internet.

“It’s like if you have a car with no roads,” he said.