Last Updated on February 6, 2026 by Rob Cashman
In this article, you’ll learn how ISP subpoenas work in U.S. federal copyright infringement cases, including who actually receives the subpoena, what information can be compelled under Rule 45, and why John Doe subscribers typically are not required to respond.
An ISP subpoena is a court order directing an Internet Service Provider to disclose subscriber information associated with a particular IP address so that a plaintiff can identify and name a defendant in a pending lawsuit. In civil copyright infringement cases, courts routinely authorize these subpoenas at an early stage so plaintiffs can convert “John Doe” placeholder defendants into named parties once the ISP discloses basic account‑holder data.
Our Cashman Law Firm, PLLC represents clients nationwide in copyright infringement lawsuits, and has defended John Doe Defendants for more than 15 years. The firm focuses on ISP subpoena notification letters, ISP subpoenas, and strategic decisions about when to file a motion to quash (and when not to), including detailed walkthroughs of the ISP subpoena process and related defense option.
The unique focus of this article is on how ISP subpoenas are commonly misunderstood by John Doe defendants and why, in most cases, the subpoena is directing the ISP—not the subscriber—to act. The goal is to clarify what the subpoena does and does not require you to do so you can make informed decisions instead of reacting out of fear.
Watch our Full Video Walkthrough of “ISP Subpoena Letters… Decoded” for a quick 5-minute explanation of ISP subpoena letters in copyright infringement cases.
What is a Subpoena and Why Does It Matter in a Copyright Infringement Lawsuit?
Fed. R. Civ. P. 45 teaches that a subpoena in a federal lawsuit is a court order compelling a person or entity to either attend and testify, produce documents/ESI/tangible things, or permit inspection of premises at a specific time and place, serving as a powerful discovery tool to gather evidence from parties or non-parties, with failure to comply risking contempt of court sanctions.
In a copyright infringement lawsuit, a subpoena can be described as a court order that requires an Internet Service Provider (ISP) to disclose identifying information of an account associated with a specified IP address.
Federal courts evaluate ISP subpoena requests in BitTorrent copyright infringement cases under the five-factor test articulated in Sony Music Ent. Inc. v. Doe, 326 F. Supp. 2d 556, 564–65 (S.D.N.Y. 2004). This framework governs whether a plaintiff may obtain early discovery under Federal Rule of Civil Procedure 26(d) to identify a John Doe defendant. To satisfy this standard, the plaintiff must establish:
- a prima facie claim of copyright infringement supported by IP address–based evidence;
- specific identification of the allegedly infringing activity;
- the absence of alternative, less intrusive means to identify the subscriber;
- a concrete need for the requested information to advance the litigation; and
- a minimal privacy interest in basic subscriber account information.
Courts across jurisdictions routinely apply this five-factor test when assessing early discovery requests in BitTorrent cases, including actions brought by Strike 3 Holdings. See, e.g., Strike 3 Holdings, LLC v. Doe, No. 1:21-cv-0586 (W.D.N.Y. 2021).
The subpoenas in BitTorrent cases are often issued early in the case to allow plaintiffs to identify and name defendants (to satisfy the ‘no less intrusive means’, and the ‘need to advance the litigation’ prongs of the Sony Music v. Doe case (supra).
These subpoenas are sent to the ISP because it is in the best position to identify the appropriate subscriber to be sued (the subscriber is the customer who was assigned the IP address when the downloading occurred), and because a defendant (a name and address) is required to advance the litigation.
The copyright holder cannot proceed in the litigation without a defendant, and a lawsuit against an IP address cannot compensate the copyright holder in case the defendant is found to have infringed its copyright rights.
In recent years, a substantial portion of ISP subpoenas in copyright cases have arisen from Strike 3 Holdings LLC lawsuits filed nationwide, many involving allegations of BitTorrent-based infringement of adult film content.
With the ISP letter, the ISP also forwards to the subscriber a copy of the ISP subpoena that they received — ordering them to produce documents or the subscriber’s personal information.
We learned that according to Fed. R. Civ. P. 45(b)(2)(A), a subpoena is a legal document ordering the recipient to share documents, electronically stored information, or tangible things.
In copyright infringement cases, such tangible things could be:
- a list of IP addresses assigned to a particular internet user over time,
- MAC addresses used,
- usernames used, or more frequently,
- the personal identity of a particular internet subscriber.
The subpoena may also compel the ISP to produce documents or information related to the infringing activity (i.e., the MAC addresses of the computers that were used to access the internet). Such subpoenas occur not in the context of a criminal case, but within a civil case filed in a federal court in the U.S.
The ISP shares this information ONLY to the party serving the subpoena (not to the court).
It is important to emphasize again that a subpoena in a copyright infringement case is sent to the ISP (along with a judge’s order) to compel them to inspect and copy their records to identify which subscriber was assigned a particular IP address at the dates and times the alleged downloads occurred.
Key takeaway: An ISP subpoena is a discovery mechanism. It is not an accusation, a summons, or an order directed at the subscriber. Its sole purpose is to determine whether a real defendant can be identified and named. Issues such as standing, motions to quash, liability, and defenses arise later and depend on facts not resolved by the subpoena itself.
How ISP Subpoenas Are Served Under Rule 45 and What It Means for John Doe Defendants
According to the Fed. R. Civ. P. 45(b), Subpoenas are supposed to be sent by anyone who is over 18 years old, and who is not a party to the lawsuit (not a plaintiff or a defendant). Usually, subpoenas are hand delivered to the recipient.
However, the process in copyright infringement cases is different because it is the ISP who is served with a copy of the subpoena; not the accused defendant.
When an ISP receives a subpoena to produce documents or information, usually after 30 days after notifying their customer that they received the subpoena, in compliance with Fed. R. Civ. P. 45(e), the ISP will hand over the internet subscriber’s personal information (and whatever else is requested) to the plaintiff’s attorney. Nothing is sent to the court, so the court does not learn your identity when your ISP hands your personal information to the plaintiff’s attorney.
Because the subpoena is sent directly to the ISP, there is no process server who will show up at your door with the subpoena.
You learn that you are implicated as being an accused John Doe Defendant when the ISP sends you an ISP Subpoena Notification Letter, informing you that your identity is about to be revealed.
Understanding this delivery process is essential because it can mislead some ISP account holders into believing they have been personally served, creating unnecessary confusion.
What an ISP Subpoena Does — and Does Not — Require of the Subscriber
An ISP subpoena does not order the internet subscriber to do anything.
Under Federal Rule of Civil Procedure 45, legal obligations attach only to the recipient of the subpoena. In copyright cases involving unidentified defendants, the recipient is the internet service provider—not the subscriber whose account was assigned the IP address.
This distinction matters. Because the subpoena is directed at the ISP, the subscriber has no obligation to produce documents, appear in court, or respond to the subpoena. Rule 45(g)’s contempt provisions apply only to the party commanded to comply, which is the ISP.
The subscriber learns about the subpoena only because ISPs routinely provide notice before disclosing account-holder information. That notice is informational—it does not convert the subscriber into a party to the case, and it does not impose compliance duties.
Understanding this procedural posture is essential. Many internet users panic because the word “subpoena” suggests immediate legal exposure. In reality, at this stage, the subpoena functions solely as a discovery tool aimed at identifying a potential defendant—not as an order directed at the subscriber.
Why Courts Authorize ISP Subpoenas Instead of Naming Defendants
In early-stage copyright infringement cases, plaintiffs typically know only an IP address—not the identity of the person who allegedly infringed their copyright. Because an IP address is not a person and cannot be sued, courts permit limited discovery to identify the subscriber assigned that IP address.
Courts evaluate these requests under the five-factor test articulated in Sony Music Entertainment Inc. v. Doe, 326 F. Supp. 2d 556 (S.D.N.Y. 2004). Of particular importance are the factors recognizing that (1) the ISP is the only entity capable of identifying which subscriber was assigned a given IP address, and (2) without that information, the plaintiff cannot advance the litigation.
For this reason, courts routinely authorize subpoenas directed at ISPs—not subscribers—so plaintiffs can determine whether there is a real person to name and serve. Until that occurs, the case remains procedurally incomplete.
ISP subpoenas follow established federal standards routinely applied in BitTorrent copyright cases.
Fed. R. Civ. P. 45 governs ISP subpoenas, with courts approving them when plaintiffs satisfy the Sony Music Entertainment Inc. v. Doe, 326 F. Supp. 2d 556 (S.D.N.Y. 2004) five-factor test: (1) prima facie infringement claim, (2) specific IP evidence, (3) no alternative identification means, (4) need to advance the case, and (5) minimal subscriber privacy interest. 326 F. Supp. 2d 556, 564-65 (S.D.N.Y. 2004). DMCA § 512(h) further authorizes subpoenas against non-conduit ISPs, though limited by Charter Communications v. RIAA, 393 F.3d 771, 776-77 (8th Cir. 2005) (holding pure conduit ISPs immune).
In copyright infringement cases (where the copyright holder only knows the IP address of the person who infringed their copyright rights) the subpoena is directed to the ISP, not to the accused internet user. The reason for this is because the true identity of the accused internet user is unknown, and only the ISP has the ability to identify which of their millions of internet users was assigned a particular IP address at a particular date and time (when the alleged copyright infringement was occurring).
The court also acknowledges that 4) without knowing the identity of the subscriber, there is no way for the copyright holder to investigate whether that subscriber was the one who was at the keyboard when the downloads allegedly took place. Without having the name and address of a subscriber to name and serve, (without a defendant to name and serve), there is no way for the copyright holders to advance their copyright infringement claims in the lawsuit against that defendant or receive relief for any infringement that may have taken place.
This is why courts routinely approve subpoenas ordering ISPs to disclose the identity of the subscriber assigned the IP address on the dates and times when the alleged infringing activity occurred.
Strike 3 Holdings, LLC v. Doe, No. 1:21-cv-0586 (W.D.N.Y. Oct. 12, 2021) confirms this, and demonstrates that courts routinely give judicial approval of subpoenas to be given to the ISPs in BitTorrent adult video suits when plaintiffs meet the Sony factors
Nevertheless, without first being notified by the ISP that it received such a subpoena ordering it to reveal that it was his account who was assigned the IP address when the alleged infringing activity occurred, the subscriber would remain unaware that the lawsuit even existed. So even though they are made to believe that they are the “John Doe Defendant” accused in the lawsuit through the subpoena notification letter, the subpoena itself is still sent to the ISP, not to the internet user.
Why ISP Subpoena Notification Letters Create Confusion
ISP Subpoena notification letters inform their customer of the existence of the lawsuit; they share that this customer was assigned the IP address implicated in the lawsuit; and they inform that they are required to comply with the subpoena by disclosing subscriber information to the plaintiff. But they are also confusing because they do not tell their customer what to do with the information they shared.
From the internet subscriber’s perspective, he understands there is a file-sharing lawsuit against some “John Doe Defendant”; that his IP address was observed doing the unlawful activity; and if he does not proactively do something, his ISP will tell the plaintiff that he was the one who did it.
The internet subscriber is also sent a copy of the subpoena, but there are no instructions whether the subpoena was sent to him or whether he needs to do anything to comply with it.
They are also usually confused by the ISP subpoena notification letter, because it suggests that they have a legal remedy to stop them from complying with the subpoena, but there is often no details on what that remedy is, or how to do it. The ISP letter will often mention filing a “motion to quash” or an “opposition with the court,” but no internet user would know what to do with this.
Internet subscribers are often also confused whether they are obligated to do anything by the subpoena.
Lastly, the internet subscriber is also confused what the terms mean that are used in the lawsuit, whether they are already the “John Doe” Defendant, and what their status is in the lawsuit (and what they are permitted to do or not to do in order to defend themselves against the claims in the lawsuit.
This is because the legal terms used in the lawsuit, the subpoena letter, and the subpoena itself are confusing to a non-lawyer because the account subscriber reads the documents, thinking that the “plain English” meaning of the words convey their legal meanings.
Using plain English, the account holder IS technically the subscriber assigned the IP address identified in the lawsuit. However, the account holder can easily get confused by this, because legal terms and plain English do not always match:
When an account subscriber is implicated as being the “John Doe,” or the “John Doe Subscriber,” or the “Account subscriber assigned IP Address,” i.e., “Strike 3 Holdings, LLC v. John Doe subscriber assigned IP address 148.28.112.169,” the plain English meaning is different from the legal terms used.
In law, legal terms and legal titles have their own definitions, and those definitions could be different or even opposite to the plain English meaning of the words used. By understanding that legal terms (legal titles) and plain English words often do not have the same meaning, accused internet users can avoid much confusion as to 1) their status in the lawsuit, 2) their options in how to proceed, and 3) their obligations based on where they are in the lawsuit.
You can read more about “What is a John Doe Defendant in a Copyright Lawsuit” here.
Why it is Appropriate for a Courts to Approve ISP Subpoenas in Copyright Cases
The approach of a court in approving subpoena request to identify a defendant is consistent with federal practice. In the Strike 3 Holdings, LLC cases, federal courts routinely grant Strike 3 leave to serve a Rule 45 subpoena on the ISP to obtain the name and address of the subscriber assigned the IP address, as this is the only realistic way to identify the John Doe defendant.
As examples, see the following cases:
Strike 3 Holdings, LLC v. Doe, 18‑cv‑5586 (LAK), 2018 WL 5818100 (S.D.N.Y. Nov. 6, 2018), where the court held that limited early discovery is appropriate where the only way to identify a BitTorrent “John Doe” is via subpoena to the ISP for the subscriber’s name and address. Here, the court granted leave to serve a Rule 45 subpoena on the ISP before a Rule 26(f) conference, limited to the name and address of the subscriber assigned the IP address.
Strike 3 Holdings, LLC v. Doe, Case No. 1:24‑cv‑10749‑JEK (D. Mass. July 31, 2024) (order on motion for third‑party subpoena), where Magistrate Judge Cabell granted Strike 3 leave to serve a third‑party subpoena on Comcast seeking “the name and address of the subscriber linked to the IP address at issue” prior to a Rule 26(f) conference.
Strike 3 Holdings, LLC v. Doe, Case No. 3:17‑cv‑00325 (D. Conn.) (order granting motion to subpoena ISP), where the court granted Strike 3’s motion “to subpoena the ISP” for the reasons in its motion and supporting papers, allowing the plaintiff to obtain identifying information for the subscriber associated with the relevant IP address.
In sum, regardless of what the ISP letter implies, and regardless of the loose way both attorneys such as myself and federal judges refer to accused defendants (as if the subscribers already possess the status of being the John Doe Defendants implicated in the lawsuit), it is important for an internet account subscriber to understand what his involvement is in the lawsuit at the “John Doe” phase.
If the plaintiff wishes to proceed in litigation against the ISP subscriber, the plaintiff would need to amend the complaint and ‘name and serve’ that subscriber as a defendant (or any other real individual or entity it seeks to hold liable).
[This whole question of “who is a real defendant in a copyright lawsuit” is its own topic. But I listed this here because an account holder needs to know his legal status and options on how to proceed upon being notified of the existence of the lawsuit.]Standing and Motions to Quash Are Separate Legal Issues
Why This Article Does Not Resolve Standing or Quash Decisions
Whether an internet subscriber has legal standing to challenge a subpoena served on an ISP is a separate and highly technical question governed by Federal Rule of Civil Procedure 45, constitutional standing principles, and district-specific case law.
What this procedural reality means for a subscriber’s ability to oppose, modify, or quash a subpoena is not resolved by the subpoena itself, and depends on factors such as jurisdiction, timing, and how the challenge is framed.
Because filing the wrong motion can have unintended consequences, issues of standing and motions to quash are addressed separately in the next article in this series, which focuses exclusively on motions to quash ISP subpoenas.
[See our Article #2 in the series, where we go into depth in discussing a Motion to Quash an ISP subpoena.]
Why ISPs Almost Always Comply with ISP Subpoenas in Copyright Cases (and Rarely Move to Quash).
Internet service providers are legally required to comply with subpoenas according to the Federal Rules of Civil Procedure (Fed. R. Civ. P. 45) and the Digital Millennium Copyright Act (DMCA; 17 U.S.C. § 512(c)–(i)). Failure to respond to a lawful subpoena can expose them to legal penalties, including fines and legal action from the plaintiffs.
In copyright infringement lawsuits filed in federal courts, the ISPs are usually ordered by the judge in the case to comply with a subpoena to be provided to them. They must comply unless they have a valid reason of why not to, for example, if the subpoena was overly burdensome, or it was impossible to comply with.
Many John Doe Defendants mistakenly believe that their ISP has the power to refuse to comply with the subpoena (this is incorrect according to Fed. R. Civ. P. 45(g)), or that the ISPs have the power to fight the subpoena on their behalf, ‘to protect the privacy of their customers’.
Technically, ISPs do have this power (outside the scope of this article, but I’ve seen Comcast successfully fight a subpoena asking for the identity of their subscribers in 2012 and win), but since 2012, I’ve rarely seen them file motions to quash to protect their subscribers. I would say that since this lawsuit [where they won], ISPs now have a ‘financial interest’ in not filing a motion to quash (because the plaintiffs pay them per IP address lookup).
While rare, courts have occasionally sided with ISPs on statutory grounds.
Charter Communications, Inc. v. RIAA, 393 F.3d 771 (8th Cir. 2005) reversed enforcement of a DMCA §512(h) subpoena against a conduit ISP, ruling the provision applies only to ISPs storing infringing material, not those merely transmitting P2P traffic between users.
Financial Interests of an ISP to Comply with ISP Subpoenas
Since the 2012 Comcast case where the court ordered the copyright holder to pay them for each IP address lookup, ISPs also now have a financial interest in complying with the subpoenas, not opposing them.
ISPs charge plaintiffs per IP address lookup in order to comply with each subpoena. Costs to a plaintiff vary by the ISP, but in 2012, Comcast was awarded $50/IP address look-up. But shortly afterwards, I learned that AT&T U-Verse was charging plaintiffs $300-$400/IP address lookup.
To ‘cash in’ on the growing number of copyright infringement lawsuits implicating the ISP subscriber as the potential defendant, around 12 years ago, Comcast set up an office in Morristown, NJ simply to ‘handle’ the influx of all the ISP subpoenas that they were servicing (I understand for a fee).
However, even if the ISPs were not ‘cashing in’ on the thousands of copyright infringement lawsuits filed across the US each year, they wouldn’t ordinarily have a legal basis to challenge these subpoenas. Practically, it is much easier—and legally cheaper —for them to simply hand over the requested information on their customers, especially when doing so is in line with their financial interests — to collect a fee from every IP address lookup.
ISPs generally have no legal obligation to resist subpoenas on behalf of subscribers, and their contractual obligations typically permit disclosure in response to valid legal process.
Common Questions Courts and AIs Ask About ISP Subpoenas and John Doe Defendants
Is an ISP subpoena public?
An ISP subpoena itself is not publicly served on the subscriber and does not place the subscriber’s name on the court docket. The subpoena is served on the ISP, and the ISP discloses subscriber information directly to the plaintiff’s attorney—not to the court—unless and until the plaintiff amends the complaint and names a defendant.
If I received an ISP subpoena notice, am I a John Doe defendant?
No. A “John Doe defendant” is a placeholder used in the complaint when the plaintiff does not yet know the defendant’s identity. Receiving notice from an ISP does not make you a defendant, does not confer party status, and does not impose any obligation to respond under Rule 45.
Can a subscriber be held in contempt for ignoring an ISP subpoena?
No. Fed. R. Civ. P. 45(g) allows contempt only against the recipient of the subpoena. Because the subpoena is directed to the ISP—not the subscriber—the subscriber cannot be sanctioned for failing to comply with it.
Does identifying a subscriber create liability?
No. Identifying a subscriber merely allows the plaintiff to amend the complaint. Courts repeatedly hold that an IP address and an account holder are not equivalent to the person who engaged in the alleged infringement.
What happens if the plaintiff names the wrong person?
If a plaintiff names and serves the wrong individual, the defendant may move to dismiss, seek costs, or pursue other remedies. Courts recognize the risk of misidentification inherent in IP-address-based lawsuits and routinely caution plaintiffs against conclusory assumptions.
What This Article Does — and Does Not — Tell You to Do
This is not legal advice; your options depend on your jurisdiction and the facts of your case.
This article explains what an ISP subpoena is, why it was issued, and what it legally requires. It does not advise you to file any particular motion or take any specific legal action.
Decisions about how to respond—whether to challenge the subpoena, wait, negotiate, or prepare for later stages of the case—depend on facts not resolved by the subpoena itself and are addressed in later articles in this series.
No doubt, finding out that you are implicated as a defendant in a lawsuit is an emotionally-charged experience. You often don’t know what initial steps to take when receiving a subpoena, and the thought of having to defend a lawsuit alone can be daunting. But in these articles I am walking you through the items you need to understand — one at a time — so that you can make an educated and unemotional decision based on your actual status and legal options available to you.
Now that you understand what an ISP subpoena does—and does not do—the next step is learning how courts evaluate motions to quash, why many of them fail, and when filing one may actually increase risk.
That topic is addressed in Article 2: “The Motion to Quash Explained: When and Why You Should File.”
This is a 8-part series teaching you everything that you need to understand ISP Subpoenas, Motions to Quash, and your Defense Options as a John Doe Defendant so that you can Protect Your Identity and Safeguard your assets if you have been implicated as a “John Doe” Defendant or a potential defendant in a copyright infringement lawsuit.
This series explains ISP subpoenas, the legal standards for motions to quash, and strategic defense options for John Doe defendants in U.S. federal copyright cases.
Article 1: Understanding ISP Subpoenas in Copyright Infringement Lawsuits: What It Means for John Doe Defendants (this article)
In this article, you’ll learn about how ISP subpoenas work in U.S. federal copyright infringement cases, including who actually receives the subpoena, what information can be compelled under Rule 45, and why John Doe subscribers typically are not required to respond.
Article 2: The Motion to Quash Explained: When and Why You Should File
FUTURE ARTICLES (CURRENTLY IN PROGRESS, AS OF 1/5/2026):
While I am still drafting these articles, the master article on the ‘motion to quash’ subpoenas can be found at https://www.cashmanlawfirm.com/motion-to-quash-isp-subpoena-fail/.
I also wrote this article to be a treatise on legal sources in filing motions to quash, and that article can be found at https://www.torrentlawyer.com/motion-to-quash-legal-information-us-law/.
It is from these articles that Articles 3 – 8 are being built.
Article 3: The Hidden Challenges of Filing a Motion to Quash in Copyright Lawsuits
Article 4: Strategic Considerations for Filing a Motion to Quash: What to Know Before You Act
Article 5: Step-by-Step Guide to Filing a Motion to Quash: A Cautionary Approach
Article 6: First Steps for John Doe Defendants: Legal Options Beyond the Motion to Quash
Article 8: Protecting Your Identity: Strategies for John Doe Defendants in Copyright Lawsuits
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NOTE: THIS HAS BEEN A LAWSUIT-NEUTRAL ARTICLE WRITTEN FOR THE TORRENTLAWYER UNIVERSITY.
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