Questions tagged [packetloss]

Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination.

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Debugging network issue

I've had this issue ever since I got this new router and flashed it with dd-wrt. It's not really impactful (I'll describe the scenario) but I'm curious about it... This is the diagram of the network ...
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Linux server dropping RX packets in __netif_receive_skb_core

I have an Ubuntu 18.04 server dropping received packets and I cannot figure out why. Here's a graph of dropped packets from netdata: The server is running multiple docker containers and networks, ...
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Packet loss (for some hosts only) issue on a Ubuntu KVM guest

I have got a Ubuntu KVM guest which has a strange issue with package loss. Certain hosts on the network (e.g. 10.140.79.100 / 10.140.79.216) I can ping with no issues but other servers (10.140.79.14 / ...
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Measure packet latency / drop between ingress and egress interface of a rate-limiting pass-through host

Somewhere between my sender and receiver, there is host explicitly limiting my transfer rate. I know it's a Linux host. The ingress interface for my traffic is eth0 and the egress interface is eth1. ...
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“Correlate” two pcap files to measure packet latency / drop rates

Imagine I have two pcap files, recorded at ingress (eth0) and egress (eth1) interfaces of a rate-limiting, packet-forwarding host. Both pcaps contain the same TCP flows, and the time base in both ...
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Why the packet loss of ping and traceroute is different

I have an IP address on 12th hop. When I send an icmp request packet with TTL 11 to this IP, the packet loss at the 11th hop is 0%. However, if I ping the IP address of the 11th hop, or use TTL 11 to ...
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How to find root cause of throughput decrease and packet loss increase?

Short summary of my issue: How or why can a stable server suddenly start to perform worse for several days, only to later (seemingly automatically) return to normal? I'm doing some performance ...
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hard packet loss through linux soft router

all! Now I trying setting up soft-router on Linux.. :( # ip rule 0: from all lookup local 20000: from all iif lo lookup main # Thanks to wurtel ! 32760: from all iif lo lookup rt2 # for local ...
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iperf test shows large number of TCP: duplicate ACK / retransmission & out-of-order

I carried out a network throughput test using iperf and captured packets at both ends. I see a almost 10% packets highlighted in tcp.analysis.flag with following characteristic: “TCP duplicate ack” ...
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Packet lost between windows Server on the SAME virtual network

Very basic Azure config. One virtual network (vnet) : 10.0.0.0/16. One default subnet : 10.0.0.0/24 A few VM plugged as DHCP on the default subnet network topology Ping is working fine since I ...
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Changing Linux kernel network settings on active live TCP sockets

If I change settings like this for example: # sysctl -w net.core.rmem_default=500000 # sysctl -w net.ipv4.tcp_rmem='4000 90000 10000000' Is it safe to do this in a heavy duty live production ...
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Ping packet loss even though the target is reachable. Does this mean packets are eventually getting through?

If I do ping 8.8.8.8 sometimes it returns the following for a period of time: From 172.22.1.1 icmp_seq=36 Destination Host Unreachable But at other times it does reach the target and yet it says ...
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Analyze Packet Loss Bursts

I need to analyze packet loss bursts in TCP streams. Given a number X a packet lost burst is when more then X consecutive packets got lost. So I have a pcap file and need to count how many bursts ...
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367 views

How to detect packet loss between two Win 10 computers?

I have an issue where an app that is dependent on file locks crashes on Windows 10. The programmers tell me that app is extremely sensitive to packet loss, so I would like to detect what is happening ...
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Packets drop in a Linux node

I've run dropwatch and this is the result I got: dropwatch> start Enabling monitoring... Kernel monitoring activated. Issue Ctrl-C to stop monitoring 39 drops at tcp_rcv_state_process+1b6 (...
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constant packet loss in internal ESXI network

I am new to Vmware Esxi and im doing testing for an experiment with an Vmware ESXI 6.0.0 server. on the server there is two Ubuntu guest clients with one VMXNET3 each, both on the same Vswitch. Upon ...
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Linux TCP/IP tuning for low throughput network?

I have two linux machines connected by a radio modem. The bandwidth is about 2kbps, with ping times of around 400ms (5% packet loss). Currently, ssh sessions have a delay in the order of 5 seconds, ...
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132 views

Periods of high packet loss, two ethernet cables plugged into TWC modem

A small business for which I am the system administrator has been experiencing intermittent internet dropouts. There seems to be no pattern to the dropouts — sometimes there is nothing for a week, and ...
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2k views

Linux bridged network intermittent packet loss (KVM context)

I have a standard bridging setup between the real world and a KVM VM guest. Bridging looks fine: [root@t ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.40f2e9c6033d ...
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695 views

multiple macvlan devices and policy based routing confusion

I have a server (ubuntu/debian) with two ISP connections. Both of these WAN connections have multiple public IP addresses. (big pipe)----eth0-->\ > server ---eth2--(...
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Fine tune a Remote Desktop Gateway server to tolerate packet losses

I have a Windows 2012R2 server acting as remote desktop gateway for a number of RDSH servers inside the perimeter, and have a firewall between it and the Internet allowing access from outside to that ...
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636 views

Effects of packet loss on video streaming

We are sending an MPEG2-TS/H264 video stream over the network. This video stream is received correctly over the LAN, instead on the other end of a private WAN video quality is poor, thus suggesting ...
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Unstable ethernet/fiber pc to pc connection Windows

We have two Windows 7 PCs (64 bit) connected to each other directly, i.e. without a router in between, using a fiber connection with two ethernet-to-fiber converters. PC1 uses a Realtek PCIe GBE ...
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166 views

Detect faulty physical links with ping

I have a question regarding detecting a physical link problem with ping. If we have a fiber or cable which has a problem and generate some CRC errors on the frame (visible with switch or router ...
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647 views

How can I identify the cause of packet loss in DNS?

We have upgraded some of our routers to Ubuntu 16.04 and are now getting some performance problems with DNS. It seems that packets are sometimes truncated, but I have no clue what else I can do: This ...
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Optimize TCP connections between two Linux hosts connected by a long lossy channel

I have two distant hosts. Packet loss is always 19% until the rate exceeds 210 kB/s. The RTT is about 220 ms. The TCP congestion control algorithm is "cubic". "f_rto" is enabled. The actual speed of a ...
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4k views

High TCP reset and packet drop count on CentOS Linux

I have a small farm of web servers (HP Proliant and IBM x, with Broadcom Corporation NetXtreme II BCM5 NIC's) running Apache 2.2.15 on CentOS 6, behind a Cisco ACE load balancer, serving a PHP/JS ...
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5k views

What is an expected TCP retransmission rate

I have a direct connection setup between my NAS and server with two gigabit links bonded in mode 0. I also have a single gigabit link from my server to my network. I want to test how the bond is ...
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381 views

Can't ping between two VMs

I have two VMs that, up until yesterday, have been able to talk to each other just fine. Now they don't. I've been trying to get this fixed for several hours now, but haven't been able to figure ...
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Is it normal to have HTTP 499 errors in 1 out of 4000 requests?

I made a website, behind CloudFlare, and sometimes I get an early terminated (nginx 499) request, which is really hard to work around in the codebase. This happens in about 1 out of 4000 requests. ...
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Troubleshooting packetloss

I currently own a couple of CS:GO gameservers which are hosted in Germany (hetzner). Recently (for the past weeks) some people have been getting weird lags (getting slightly teleported back, some of ...
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VMWare vSphere packet loss

I have a Dell Blade Enclosure with 14 blades and ESXi 5.5 on it. On blade 7 and 14 I have round about 65 % packet loss when I ping the ESXi Management interface. On all other blades there ist no ...
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Packetloss over Internet for “Linux-Linux” but not for “Windows-Linux” (tl;dr: it's MTU)

I am right now getting additional grey hair fighting a phenomenon concerning packet loss between machines on the Internet. Check the diagram below. Note that whenever I use "SSH" I could use "HTTPS"; ...
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788 views

OSX how to drop packets randomly

I am testing the resilience of one of our streaming applications to handle packet losses. On linux machines I normally use iptables to randomly drop packets like this: iptables -A INPUT -m statistic -...
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ICMP Packet Flood a local device over Wireless AP to figure out packet loss?

I'm using a utility to create an ICMP packet flood/attack called Hyanea since windows doesn't have native support like linux does. I want to be able to test a new AP to see if any packet loss occurs....
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Determine which equipment is causing packet loss

I'm connecting from my office to two servers (server 'A' and server 'B') hosted by two different providers. Since a few days, my connection speed to server 'A' has dramaticaly slowed down. Even when ...
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592 views

How does ifconfig calculate packet loss?

Does the dropped packets output of ifconfig refer to the number of frames lost on the local subnet (i.e. datalink layer) or the number of lost IP datagrams at the IP layer or is it TCP retransmission ...
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410 views

Printer dropping packets while in standby mode

We have an HP LaserJet Pro 400 M401n connected to a Brocade ICX6450-24P that is having some intermittent connection issues while it is in standby mode. I have a feeling there might be some electrical ...
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372 views

TCP/IP ack loss between firewall and server

Scenario: Client connects to Server using TCP/IP. Issue: During initial TCP/IP connection setup, the ACK packet [3rd step in TCP] sent from Client to Server has crossed the firewall [evidence from ...
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Intermittent Network Instability

I have an office network being run by a Linksys WRT1900AC, and I'm experiencing significant, but intermittent issues. I have between 15 and 20 devices connected to it, including computers, phones, ...
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packet loss rate and netem

I am emulating a network with netem. I wrote a script that changes the network delay according to a linear function from 1 to 50ms every 15 seconds (with a normal variance = 5%). The packet loss is 1%....
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RTNETLINK answers: Invalid argument while specifying packet loss by tc command

I am trying to specify packet loss by tc command on interface (port) 1 of switch part of network I have created using mininet : sudo tc qdisc change dev s1-eth1 root netem loss 0.1% but gettring ...
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Track Source IP of dropped packets

I've got a Linux server running CentOS 7, and I've been facing an issue where the RX dropped packet count keeps increasing. I believe it may be caused by a faulty cable/connector in the network; ...
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Corrupted files when downloading with HTTP

With my UMTS connection most archives > 50 MB are corrupted when downloading them via HTTP. If I switch to HTTPS the problem is gone. The problem should not reside in my network, because I have an ...
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Network sensor for a TCP connection for collecting statistics each second [closed]

I need a Network Sensor capable to gather basic end-to-end statistics (packet loss, jitter and network delay/RTT) of several TCP connections directed to the very same destination (ip-addr:port) on ...
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Patch panel confessions

So the old IT guy was a college student with no experience prior to be hired beyond some classes. The one before him had no experience at all and just did his best with what he had. Now I am here and ...
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Extreme UDP packet loss at 300Mbit (14%), but TCP > 800Mbit w/o retransmits

I have a linux box I use as the iperf3 client, testing 2 identically equipped Windows 2012 R2 server boxes with Broadcom BCM5721, 1Gb adapters (2 ports, but only 1 used for the test). All machines are ...
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564 views

Fortinet Ascenlink heavy packet loss

I'm working on a company with some Fortinet appliances. One of them is a Load Balancer named AscenLink. The specific model is an AscenLink AL-700. There's a insane problem: a huge packet loss on the ...
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burnt Switches connected directly to the internet

We got a setup with a switch between the cable modem/bridge and the two router ports. We burn this switch every 6 months, and it has to be replaced. Symptoms are heavy packet loss or in general very ...
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852 views

TCP High Send-q coupled with FIN_WAIT1 status

I'm having a problem with one of my webservers, which is taking minutes to completely render a web page. I had a look at the TCP connection and noticed that I have a very high value in the send-q ...