[stylin19a]

When did the FBI start monitoring the DNC servers ? and they would have needed a warrant ?

July 27, 2015 – Russia’s cyberattack on the DNC began only weeks after Trump announced his candidacy for President of the United States.
September 2015 – the FBI notified the DNC that hackers had compromised “at least one DNC server.” The FBI called the DNC Help Desk.

[Cboldt]

-- When did the FBI start monitoring the DNC servers ? and they would have needed a warrant ? --

Good questions.

[Cboldt]

-- When did the FBI start monitoring the DNC servers ? and they would have needed a warrant ? --

Different sources ...

September 2015: FBI Informs DNC of Russian Hacking - The Moscow Project - NYT

The Perfect Weapon: How Russian Cyberpower Invaded the U.S. - NYT

Looks like FBI awareness may have arisen from reports to it, from others. Phishing email, perhaps with "To" headers that included DNC, or maybe the intrusion was used to send further phishing spam, this originating from DNC servers. You've likely received e-mail from a friend whose system was infected.

Yared Tamene, the tech-support contractor at the D.N.C. who fielded the call ... "I had no way of differentiating the call I just received from a prank call," Mr. Tamene wrote in an internal memo, obtained by The New York Times, that detailed his contact with the F.B.I.