12
votes
1answer
1k views

Why is my TCP throughput much greater than UDP throughput?

I haven't done anything unusual to my hardware or kernel configurations (all default settings, fresh OS install, Linux kernel 3.11 TCP/IP stack) and I'm averaging about 3.83 million messages per ...
1
vote
1answer
397 views

Multicast UDP not working

Multicast UDP on raspberry pi I haven't narrowed things down enough to know if my issue is because of debian, raspbian specifically, or if I am just missing a something completely. I have a python ...
2
votes
1answer
208 views

tftp transfer painfully slow

I am using HPA's tftp server for PXE boot. When I try downloading an image from my tftp server using curl, the transfer rate is less than 3 MB/s, even on my 1Gb network. curl -o initrd.gz ...
3
votes
1answer
278 views

How to use netperf on specific NIC port?

I have two servers, SERVER and CLIENT. Each server has its own onboard 1 GbE ports, and its own NIC with a 10 GbE port. SERVER and CLIENT are interconnected on both a 1 GbE switch (administrative ...
1
vote
0answers
64 views

setting up a local VoIP to use as a Wifi Headset

I had this idea of using Wi-fi in a vehicle to connect my cell to the car call handler.Just as it works with bluetooth nowadays. Just to demonstrate that such a thing is possible , i had three Linux ...
1
vote
0answers
86 views

Command for finding open ports

On my linux servers I have this alias set: alias ns="sudo lsof -Pi|grep -v ESTABL|grep -v CLOSED|grep -v -e '->' | tr -s ' ' '\t' | awk '{print $3 "\t" $8 "\t" $5 "\t" $9 "\t" $1}'| column ...
0
votes
0answers
87 views

How to make Network alive but speed low, slow for upload, download?

I have own application written (Python, Java) which does upload/download for streaming. Now in my local office network and home network setup i can't simulate slow/low latency network (as a result i ...
2
votes
1answer
1k views

TCP buffers keep filling up (Recv-Q full): named unresponsive

Using netstat -an, I set the message that the Recv-Q is full. It is filling up to the rmem_max: Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address ...
3
votes
1answer
54 views

Per executable UDP port redirection possible?

I have a black box program which listens on a particular UDP port. I'd like it to listen to a UDP port of my choosing. Is there a way to trick the executable into listening on a differen port. I ...
0
votes
1answer
69 views

How do I verify that the Linux kernel is not freezing when uploading or downloading large data over the ethernet interface?

How to verify if the Linux kernel is doing what it's saying for network interfaces? I have one network interface eth0 which has hardware support to do 1GB full-duplex. I have prepared 2 box. Now ...
1
vote
2answers
84 views

Can an arbitrary process read data coming to/from a network port? How?

For example, postgres does the following as shown with lsof -i: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME postgres 29200 postgres 8u IPv6 470362 0t0 UDP ...
0
votes
0answers
354 views

Tools to find OpenVPN UDP packet corruption

Are there Unix tools to troubleshoot UDP packet corruption? I'd like to avoid writing my own... I think ping might report when a packet is corrupted, but it doesn't really seem to have options ...
1
vote
0answers
91 views

Cannot see an EC2 VPN server from another EC2 instance

I'm using openVPN to connect to one EC2 instance from another. The client cannot see the server, however, despite that servers outside of AWS can see the server and successfully negotiate with it. ...
1
vote
2answers
226 views

How to find transmission speed?

Two host machine's one as a client and other as a server, i am testing udp load-test in these two machines.Machine Ethernet speed is 100 Mbps but i want to send 30000 packets each of 512 bytes at 1 ...
3
votes
0answers
790 views

I can SSH and HTTP, but not ping or access particular UDP services over my LAN

So I've encountered a weird problem when trying to set up a Linux server running a variant of CRUX Linux. I am trying to configure it to be a Teamspeak server, but no clients can connect. The ...
1
vote
1answer
1k views

Scan one or all ports, on UDP or all protocols, to see if I'm getting, what I suppose to get

I have a GPS localizer (TK102). I've set it up to send responses over GPRS to particular IP and over particular port. I was told that, it uses UDP. It seems that something is being sent (paid ...
3
votes
1answer
620 views

Why isn't my application receiving broadcast packets?

I have written a Qt application that listens for UDP broadcast packets on the network interface p2p1. I have installed the application in Fedora 17 i386 in a VirtualBox VM. For some reason, the ...
3
votes
1answer
2k views

Why would my Linux host suddently stop receiving multicast? All other nics on private network are receiving

Here is my dilemma. Suddenly, as of yesterday, multicast packets are no longer being received from eth1 (private gigabit network) from one node. Routing between all the nodes is fine, no collisions, ...
2
votes
1answer
423 views

ICMP destination unreachable

I am working on an Arch Linux machine with an ethernet interface eth1. I have created the interface eth1:0 using ifconfig and given it a dummy hardware address (00:01:02:03:04:05). When I send a UDP ...
1
vote
2answers
440 views

UDP NAT Punching

I have the following two problems. Please help me to solve them: In symmetric NAT, as I know, the local hidden node (behind the NAT) must initiate connection in order to create a window in the NAT ...
2
votes
2answers
306 views

UDP multicasting broken after kernel update

I've got an embedded system which is running a stripped down Gentoo userland with a manually build kernel. The system acquires data from a PCI card and sends it out to an UDP multicast group. All ...