DayZ DDoS Attack: How StalkerZ Survived 643 Gbps
Four changing attack rounds against StalkerZ: our account of a 643 Gbps campaign peak, forged DayZ packets and the filter updates that followed.
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The Community at Stake
StalkerZ runs a STALKER-themed DayZ roleplay community. For a server built around factions and ongoing characters, an outage interrupts more than the current match. Players need to know they can return to the world they have invested in.
Our account describes a campaign lasting more than 24 hours, with four changes in attack behavior and a reported peak of 643 Gbps. The peak was not sustained for the whole campaign. As the traffic changed, we updated the filters.
The surviving record includes two traffic captures and a Discord message from Harry, who identifies himself with the community. Together with our account, they show why this became an exercise in adapting the DayZ profile, not just absorbing a large flood.
What Is Game-Aware DDoS Protection?
A packet can arrive on the right port and carry a familiar header without belonging to a player. Game-aware protection adds packet-structure and session checks to network-level controls so those decisions do not fall entirely to the game process.
The active product and profile matter. OVHcloud documents a Layer 7 Game firewall on eligible products, with support varying by range. The comparison to make is which traffic a configured profile checks and what it does with it.
The Previous Host
Our migration account says StalkerZ moved after recurring attack-related problems. Harry’s message describes his dissatisfaction with the previous hosting experience.
We do not have the former product configuration or packet captures. This is an account of the migration and our response, not an audit of the previous provider.
The Attack Types Described in the Account
We described three types of traffic during the campaign: volumetric flooding, A2S query abuse and packets imitating DayZ traffic. The charts below preserve activity from the incident; the vector descriptions come from our account.
Layer 1: UDP Volumetric Floods
At the network layer, the job was to handle the flood before it reached the server. Our account put the campaign peak at 643 Gbps. Packet rate mattered alongside bandwidth: the amount of data and the number of packets are different pressures on a filter.
Original burst view labeled “per 30 seconds”, indicating sampling granularity rather than a 30-second attack duration. The left-axis values are clipped.
Layer 2: A2S Query Abuse
A2S is the Steam server-query protocol used for server listings. A2S_INFO requests follow a standard format, illustrated here:
[FF FF FF FF] [54] [Source Engine Query\0] └─ Header └─ A2S_INFO type byteThis is a protocol example, not a packet recovered from StalkerZ. An implementation can require a challenge response before answering the query. Valve’s protocol announcement explains how that A2S_INFO challenge helps resist source-spoofed reflection.
For an owner, the distinction is practical: protecting game sessions does not automatically protect the query work that makes the server visible in a browser. Our KarmaKrew case study covers that path in more detail.
Layer 3: Packets Imitating DayZ Traffic
The next problem was traffic that looked enough like DayZ to need more than a port or volume check. A recognizable header is not proof of a valid session.
Our account describes using VxShield’s kernel-level DayZ profile to check packet structure, session context and rates. Rejecting traffic before the game process sees it moves that work out of the application. The retained record does not include the forged payloads themselves.
The DayZ DDoS protection guide explains how the game, query and RCON rules fit together.
The Migration and Changing Attack Rounds
After StalkerZ moved to our DDoS protected DayZ hosting, the campaign changed in four rounds. This sequence comes from our incident account; the image is a separate view of campaign traffic.
Original campaign view. Individual spikes cannot be assigned to narrative rounds or uptime outcomes from this image alone.
Round 1: UDP flooding arrived alongside A2S query abuse. That put the network and query paths in scope from the start.
Round 2: Packets imitating DayZ traffic brought session and payload checks into the response.
Round 3: A distributed push reached the reported 643 Gbps peak. We described a custom filter update in response.
Round 4: Changed payloads prompted another update. Our account says the campaign stopped after this round.
The useful lesson is in that sequence. One rule was not the whole response: the profile needed to follow changes in the traffic it was judging.
The Reported Results
We reported continued server availability through the campaign. Independent uptime monitoring and player-session logs are not retained here, so that remains our reported outcome.
Harry’s message gives the customer’s view of the move and the protection. His wording is preserved in the original screenshot.
Harry’s retained Discord message. Its numeric date format does not establish an unambiguous calendar date, and the message is not an uptime log.
What to Check in a Game Protection Profile
An owner should be able to ask what happens on each traffic path and get an answer more specific than “DDoS protection included.”
| Area | Evidence to request |
|---|---|
| Network limits | Both bandwidth and packet-rate behavior |
| A2S queries | Supported request types and challenge/cache handling |
| Game packets | Profile scope, structure and session controls |
| Incident response | Logs showing rule changes and deployment timing |
| Player impact | Game-session and availability records |
Keep those records together during an incident. A traffic graph helps explain the attack; game and session records help explain what players experienced.
For the development story, read how we built DayZ-specific DDoS mitigation. If you are investigating a connection problem, start collecting network evidence with the WinMTR report guide rather than assuming every failure is an attack.
Common Questions
How do I protect my DayZ server from DDoS attacks?
Cover the network, game and query paths. Ask about bandwidth and packet-rate capacity, DayZ structure and session checks, and supported A2S handling. Confirm which profile is active on your server and keep incident records.
What is the difference between generic and game-specific DDoS protection?
Network controls handle traffic volume and rate. Game-aware profiles add checks against the game’s packet structure or session behavior. The useful comparison is the active product and profile, not a generic protection label.
Can DDoS protection stop protocol-level attacks on game servers?
Structure and session checks can reject crafted packets that simple port or volume rules miss. They work alongside query, rate and network controls; no profile guarantees that every attack will be blocked.
Why do DayZ servers get DDoS attacked?
The motive in this campaign is not known. For an owner, preparation does not depend on guessing it: protect the traffic paths, record incidents and have a response plan before players lose access.
Review Your DayZ Protection
Check the active rules on your game and query paths before an incident. Decide who will collect logs, who can change the profile and how you will check that players can connect.
VYKIX includes VxShield with its plans. Confirm the active DayZ profile and the responsibilities for your hosting product. Open the live portal for your exact VAT-inclusive total and any unavoidable fees before payment.
Moving from another host? The current switcher offer includes best-effort migration and seven days added to the paid plan after VYKIX confirms eligibility and scope. Terms apply.
Move your DayZ server to VYKIX | Ask VYKIX on Discord
Read the KarmaKrew A2S case study for query-protection context or the 2.56 Tbps Ground Zero case study for a detailed network report. For configuration, use the DayZ DDoS protection guide.
Game-aware DDoS protection for your server.
Run your game server with VxShield included. Ask about free migration and seven days free for eligible customers switching hosts. VYKIX confirms the scope, timing, and terms before the move.
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