1
vote
0answers
34 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?
2
votes
2answers
317 views

Network flooded with seemingly empty packets

Let me preface this with the fact that I'm just a web developer at my company with little networking knowledge. Earlier today there was a department that lost all of their network connections so I ...
2
votes
1answer
1k views

Packet flooding, is there any way to handle it?

My machine is being flooded with thousands of packets per second. They don't eat much bandwidth (60mbps out of 1gbit) but they damage system a lot by consuming a CPU responsible for handling network ...
2
votes
2answers
2k views

Switch Floods Packets that should be Unicast

I work as a Network Admin in a big company. Lately we noticed an issue with our network infrastructure. Basically our network backend lies on a Catalyst as main L3 backend switch, and few Cisco Nexus ...
2
votes
1answer
1k views

Protecting against UDP flood

One of my servers is being flooded with udp packets on random ports. 12:11:54.190442 IP 182.48.38.227.60173 > localhost.51523: UDP, length 1 12:11:54.190447 IP 182.48.38.227.60173 > ...
0
votes
5answers
447 views

TCP attack invisible to netstat

we are hit by a strange attack, the attacker even emailed to challenge us. The output of "netstat -n" is just a few "ESTABLISHED" and "TIME_WAIT" typically, yet the server's website cannot be reached ...
0
votes
1answer
444 views

How does ospf control flooding?

What method is used by ospf protocol to prevent looping of flooded packets for link state advertisements? The packet header does not contain any timestamp. How do the routers recognize that it is the ...
1
vote
2answers
393 views

Finding Evidence of a Denial of Service Attack (Linux)

We had a Gentoo Linux server (that was updated weekly or bi weekly) that higher ups claimed did a denial of service attack on the whole local network and brought it down. Are there any log files we ...