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4
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1answer
197 views

Finding google unusual traffic

We are a small Internet provider. In order to get Internet access we are using NAT (10-20 users per one public IP). And lately we've met with Google blocking services (captcha and full block) and we ...
1
vote
1answer
615 views

Firewall UDP Flood Dos/DDoS

Recently I have been suffering from what appears to be a UDP query flood attack. I am looking for a way to block the attack using a software firewall such as iptables, this should be possible, as ...
1
vote
1answer
177 views

Stange stream of HTTP GET requests in apache logs, from amazon ec2 instances

I just had a look at my apache logs, and I see a lot of very similar requests: GET / HTTP/1.1 User-Agent: curl/7.24.0 (i386-redhat-linux-gnu) libcurl/7.24.0 \ NSS/3.13.5.0 zlib/1.2.5 libidn/1.18 ...
0
votes
1answer
69 views

Strange NetBIOS query with old computer name

I've one computer in our network which I first named PC029. Shortly after I changed its name to PC021. This was more than a year ago. Today I've found (thanks to Wireshark) that this computer is ...
0
votes
1answer
103 views

How to prevent TCP network flood triggered by KVM VPS clients?

How to to protect nodes/ detect and block KVM VPS clients that TCP flood the network ? I use SolusVM VPS management system. Recently one abuser toke several VPSs and flood it the datacenter network. ...
0
votes
1answer
161 views

Strange TCP Flood / Flood from Port 445

Good Evening. Today I noticed a strange flood on a box that I am working with, here is a dump from tcpdump: 23:21:07.580917 IP (tos 0x0, ttl 64, id 5746, offset 0, flags [DF], proto TCP (6), length ...
0
votes
1answer
128 views

How shared hosted web servers deal with spam (flood) attacks?

I want to know how shared webhosting or other types of it deal with Spam issues. Example: stop serving the website for a period of time, and how much is it? ...
1
vote
0answers
65 views

Fail2ban floods and slow response time

I tried searching for this; I found many people asking but I wasn't successfully to find a working (for me) solution. I have an application that logs each connection on a custom log file. When ...
1
vote
0answers
51 views

ICMP DDoS, proper ACL?

We are having about a 3-4Gbps ICMP flood on one of our servers and I wonder.. I have a 20gbps of DDoS protection but the proetction seems ineffective against ICMP funnily (it worked well to block a ...
1
vote
0answers
282 views

Protecting network from a broadcast storm

We have a flat office network tree built on a number of different ProCurve L2 and L3 GigE switches that spans some 300 ports. Today I found that one of the devices in the network for a short period of ...
1
vote
0answers
272 views

How to block hping3 SYN ACK efficiently with iptables?

I'm trying to execute a TCP SYN flood on my Debian web server with nginx. Executing tcpdump "tcp[tcpflags] & (tcp-syn) != 0" while flooding, I see all packets coming. iptables seem to work well ...
1
vote
0answers
4k views

ntopng: Host XXX.XXX.XXX.XXX is a flooder [NNN new flows in the last 3 sec]

I am exploring ntopng reports on my router and seeing, that one computer on my LAN is a flooder. ntopng says Host XXX.XXX.XXX.XXX is a flooder [NNN new flows in the last 3 sec] How to explore these ...
1
vote
0answers
149 views

Network flooded with LLC packet

Recently my network has been slow. From Tcpdump i found lot of frame with protocol LLC. A complete packet capture can been here tcpdump result Any hints on interpreting these packet?
0
votes
0answers
182 views

GET /wpad.dat entries flooding my access_log

I have a small LAN of some 30 users in it with proxy auto configuration enabled and working. Two of them are requesting wpad.dat file too rapidly at a pace of 30 times per second. 10.1.14.246 - - [...