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0
votes
2answers
170 views

SYN packets sent from one server but never arrives at destination

I am troubleshooting network problems for a client, remotely. The problem they have is that they get "connection timed out" occasionally between a web server and and a back-end search server. They can ...
6
votes
1answer
705 views

Varnish running out of open ports, lots of SYN_SENT connections

Recently we've been experiencing issues with our Varnish (3x) -> Apache (3x) setup, resulting in a huge spike in SYN_SENT connections. The spike itself is due to the amount of new traffic hitting the ...
1
vote
1answer
139 views

Detecting a host doing a port sweep across multiple interfaces/networks

I'm trying to set up a honey-pot like machine that would detect port sweeps from multiple networks with multiple interfaces. As an illustration, if I could set up a box with eth1, eth2 and eth3. ...
0
votes
1answer
66 views

Spam Traffic, DDOS Attack & Server Crashing

I am running phpfox application in my server under my main domain name fetlock.com and I am getting large amount of spam and also suffering from DDOS attacks from multiple IP addresses. My server ...
0
votes
1answer
298 views

how to forward all traffic on specific interface to ip address

I have one Linux machine that have 2 interfaces. The first one is used as a default one and provides access to internet, the second interface was added as a dedicated link to send packets from tcpgen ...
0
votes
1answer
491 views

log openvpn traffic by squid

is any way to log openvpn traffic (sites that users visited)? i think because openvpn use tunnel and encrypt traffic cannot log visited websites, but in a server i saw that open vpn's users traffic ...
2
votes
0answers
310 views

curl request results in heavy load on the server

We consume an XML Datafeed by sending cURL requests to the provider's server. They do not allow us to cache, so each pageview is a new cURL request. Twice this year, our server has crashed with the ...
0
votes
0answers
241 views

How can I redirect/forward all the UDP/TCP traffic on one interface to another interface in OpenWrt

I am new to networking and I have a measurement device (D) that periodically sends all its readings over few UDP multicast sockets (with different multicast IP addresses and different port numbers). ...
0
votes
0answers
141 views

iptables configuration to block unwanted traffic on specific MAC addresses

I want to block all Skype,Facetime, VOIP traffic on a MAC address. My approach is to block all ports from 450 to 65535 and this is my commandline: iptables -A INPUT -p tcp -destination-port 450:65535 ...
0
votes
0answers
46 views

Imbalance between DNS query and response rates

The following figures shows the rate of UDP DNS queries and responses of a traffic passing a router. DNS query is a DNS packet with query/response flag set to 0 in header and DNS response the one with ...