A denial-of-service (DoS) attack is an attempt to deny service to legitimate users by sending extreme amounts of requests to a server.

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CSF/LFD - would I really need CPHulk enabled also?

So if I have the default configuration of CSF/LFD firewall running, should I enable CPHulk, or does CSF/LFD already do what CPHulk does? If the answer is "No, CSF/LFD does not do what CPHulk does", ...
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Firefox 43: Uploading to Youtube results in DoS behaviour

I've been trying to upload a video to my channel today, only to notice that Firefox starts using 100% CPU time on a single core and then suddenly, I and everyone in my household can't connect to the ...
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I can access websites through the web browser, but I can not ping them or interact in various other ways

as of around two weeks ago I've been having really weird interactions with the Internet that I can't explain, but please keep reading. I've tried looking for the issue myself and haven't found ...
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How can I bridge my router to my Linux OS?

I am getting ddosed a bit so I want to send all my router traffic to my Linux OS as a somewhat mitigation. How to send my router traffic to my machine?
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DOS attacks using cmd and protection against them

After finding someones ip you can easily send pings to them to make DOS attacks. Me and my friend tried to make a defense against them and wanted to know how a low level attacker can send this DOS ...
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DDoS/botnet or what's going on, cloudflare.com?

This is small output from tcpdump -i re1 'port 25': 14:00:10.732034 IP cf-190-93-254-113.cloudflare.com.http > MY_IP.smtp: S 4234708404:4234708404(0) win 8192 <mss 1412,nop,wscale 8,nop,nop,...
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DDOS on port 443?

Recently my friend asked me whether his network is secure because he is setting up a game server on port XXX. I opened up Nmap on my linux machine and found port 443 opened. I tried to access https:...
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Compromised Debian server sending DDOS attack

I have a server online that apparently has been compromised and it sends DDOS attacks to another ip. The system is a debian 7 server, hosting a few wordpress, joomla websites, and airtime to host a ...
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Can Torrent/DHT network remember my IP?

I suspect that my torrent activity casted some sort of "natural" DDOS attack on me. I had UPnP configured and each time I was starting uTorrent client, it was generating new random port and was ...
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Measure DDOS attack strength

I have been puzzled on this theory. Assume Server B is sending DDOS attack to Server A, so is it possible for a random client A, to be able to measure the attack strength, like the client A was able ...
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Logging incoming IP addresses on a specific port

I've tried tcpflow and iptables but I'm unable to do so. I believe someone is attempting to DDOS my open port which is a server, so that my clients are unable to connect. From tcpflow I'm able to get ...
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MacBook Air gets added to Watchguard XTM-21W Appliance's Blocked Site List?

We have this issue where one of our MacBook Air (Mountain Lion) users is periodically getting added to the Blocked Sites list within our Watchguard XTM-21 Appliance (XTM21-W). Couple of questions: ...
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Protected from attacks through Skype

I know that people can find your IP through Skype and try to DDOS it and take your Internet down for a couple of minutes or hours. What I would like to know is: How many people need to DDOS you at ...
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How to get rid of DOS attack: RST Scan?

I have Netgear Wnr1000v2 router. I have set my NAT to secure mode ( I don't know if that helps ). Many a times when I see my router's log I see lots of DOS attack: RST Scan. I somehow think that these ...
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How to mitigate IP fragmentation attacks before reassembly when authentication information is available?

I'm trying to filter incoming traffic to high bandwidth, low latency network, to mitigate DDOS. The incoming traffic is custom UDP (I'm setting the protocol specs so I can force IP headers if ...
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Implementing fail2ban the correct way

I have a Django web app where people write comments and upvote/downvote others' comments. The webserver is gunicorn + nginx (reverse proxy). The db is postgresql. The db and web app reside in two ...
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A lot of random NAT tables appear

My brothers Mac seems to be infected. It keeps on sending UDP and SYN floods to our router, and it multiplies my ping 10 times.When I look in the NAT Mapping table there are a lot of random address ...
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Block packets by size in Windows

currently I am receiving an attack against one of my services running on Windows Server 2008 R2 with malicious UDP packets all of a specific length. I have tried dropping these packets with a plugin ...
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How to analyze a suspicious traffic under linux machine?

Often under Linux machine, networks are protected by firewalls. This protection, though necessary, do not detect external attacks. Indeed, a Firewall is designed to block unwanted network flows while ...
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My modem Comtrend VR-3031eu

I found this setting in my modem, how to configure it?
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Configure Router for better DDoS protection Actiontec MI424WR

So for the past month, my server has been attacked by script-kiddies three times. The server is mainly used as a minecraft server. I am getting worried that this is becoming an outbreak as many of ...
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Linux message: Possible SYN flooding on port 25. Sending cookies

I have a Linux CentOS server online. At my console this message appeared: possible possible SYN flooding on port 25. Sending cookies. See SYN flood and SYN cookies. I have done an Apache JMeter ...