# DoS Attack (UDP Flood) **URL:** \ **Category:** Wowza Streaming Engine\ **Created:** [December 10, 2013, 10:44am UTC](https://community.wowza.com/t/dos-attack-udp-flood/40474 "2013-12-10T10:44:54Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Gordan\_Grgurina](https://avatars.discourse-cdn.com/v4/letter/g/c68b51/32.png) [@Gordan\_Grgurina](https://community.wowza.com/u/Gordan_Grgurina)\ **Post date:** [December 10, 2013, 10:44am UTC](https://community.wowza.com/t/dos-attack-udp-flood/40474/1 "2013-12-10T10:44:54Z")
Hi, I’m experiencing a problem. Streaming is not always available. It 10 minutes works, and 10 minutes not. I suspected the network card since it has a known problem with the version of Ubuntu that I use. So I changed the network card but the problem remained. Only after that I found in the router log files records of DoS attacks. Router recognizes the problems, but it not stopping them. Should I solve the problem on the router or the Wowza server? I have read a dozen of posts on the forum but I have not found similar problems. I do not know anything about security and none of my colleagues know about DoS attacks and how to solve them. Firewall [ICMP]: Drop Incoming 212.92.206.133-\>212.x.x.x DOS [UDP]: Attack Incoming 86.27.254.86-\>212.x.x.x [UDP Flood] and before I had and this one: DOS [UDP]: Attack Incoming 198.100.153.127-\>212.x.x.x [UDP Echo Chargen] ---
**Author:** ![sal\_jefferson](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@sal\_jefferson](https://community.wowza.com/u/sal_jefferson)\ **Post date:** [December 10, 2013, 11:09am UTC](https://community.wowza.com/t/dos-attack-udp-flood/40474/2 "2013-12-10T11:09:46Z")
This article shows how to blacklist IP addresses: [How to blacklist by IP](https://www.wowza.com/docs/how-to-blacklist-by-ip-moduleoverrideplayblacklistip) You may also want to research securing your router. Salvadore