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Questions tagged [packets]

54 questions
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Wireshark and mirrored ports bringing in 10k+ packets a second

I've got wireshark setup on a monitoring machine to monitor our offices internet traffic (approx 40 machines). However, whenever I start wireshark within about 30-40 seconds it has crashed - I think due to the large volume of packets being received…
buzzmonkey
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Reject all mail packages on all ports (outgoing) on Ubuntu

I just had a problem with our ISP; our internet connection was blocked because there was to much mail being send from our ip. The problem is that we all use gmail and that no mail is being send through the ISP SMTP server as far as we know (ISP…
WesleyE
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My computer is sending ICMP packets to arbitrary destinations

My computer is sending ICMP packets to arbitrary destinations. I can't understand the reason. Dump of one of the packet is : Internet Control Message Protocol Type: 3 (Destination unreachable) Code: 3 (Port unreachable) Checksum: 0x811b…
user58859
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How to set the UDP Packet Size with iperf3?

How to set the UDP Packet Size with iperf3? The flag "-M" does not work with iperf3. Is there an alternative?
Jimmy88
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tcp previous segment not captured when NAT

I have a client request web service on a server behide NAT. My client IP is 10.54.10.193 NAT address: 10.54.28.183 Server address: 62.209.39.203 When client request web service on server we have TCP previous segment not captured as image below: But…
moodym
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Setting ToS/QoS for VoIP on Mikrotik

I have a Mikrotik router which looks like iptables. I need to setup QoS to ensure VoIP phones get top traffic priority. How do I know what ToS to use and how would I get it? I searched and can't seem to find the ToS for VoIP. My rule set so far is…
Jason
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Opening a port to only one external ip address

I want my port 2255 on 192.168.1.101 to accept and send packets only from and to 74.22.22.22 What settings needs to be added on the windows firewall and my router?
nikhil carvalho
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Best way to trace outgoing requests from a server

We have an Ubuntu 14.04.1 LTS server with nginx 1.4.6 that hosts a few dozen websites and received an abuse complaint from another server of hundreds of requests like this: "POST /wp-login.php HTTP/1.0" coming from our server. How can I go about…
Craig
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What do other nodes do with a switch's packets the first time the packets are sent out?

When it comes to switches I learned that the first time packets are sent from one node to another, the packets are sent to all nodes on that network. The switch then remembers where, for example, Computer A is trying to send the packets to (Computer…
Space Ghost
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Is there a way to explicitly set the maximum number of packets tcpdump will capture before terminating?

We have a small script that essentially does the following: A) Capture packets using tcpdump and pipe to output file. B) Run our own clean + sort script on output file. C) Display results using | sort | etc etc... So, we were wondering if there is…
anonymous-one
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F5 Packet filtering or iRules or both?

I need to set-up a custom filter for a virtual host that requires both ip address checks and URL check. Like so: _if_ _(_ http-request matches url _and_ ip is from certain host/net range _)_ _or_ ip is from a certain VIP range _then_…
iddqd
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Duplicate syn packets sent from Windows server 2003 sp2

My pc is running Windows server 2003 sp2. Whenever I establish an internet connection (e.g., with internet explorer to google.com), my host sends the syn packet twice. It is (probably not) a retransmit as the two syn packet are sent within a 0.01 ms…
user141400
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iptables/haproxy limit packets per second

Is it possible to limit incoming tcp packets per second (or bytes per second) with iptables or haproxy? I have found many examples but none of them seem to work.
Ryan
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irqbalance on linux and dropped packets

I am investigating dropped packets on a dual core, quad XEON box running Linux. One thing I see is irqbalance running on the system. I have a couple of questions. Reading the docs here I think I understand how it is supposed to work, but one…
Andy F
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Can someone give me advice on these rules to prevent DDOS where fragmented packets are sent without the initial SYN fragment ?

iptables -N NEW_TCP_PACKETS_NO_SYN iptables -A INPUT NEW_TCP_PACKETS_NO_SYN -p tcp ! --syn -m state --state NEW -m limit --limit 10/day -j LOG --log-prefix "New packets but not syn:" iptables -A INPUT NEW_TCP_PACKETS_NO_SYN -p tcp ! --syn -m…
Kris
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