2
votes
0answers
67 views

Full MTU not utilized with jumbo frames enabled

I've been testing to see if I can get any benefit from enabling jumbo frames. I've set up two identical Dell R210 servers with Xeon quad core E3122 CPUs, 8G of RAM and Broadcom NetXtreme II BCM5716 ...
0
votes
0answers
75 views

Ethernet link not detected under Linux 3.6.9, but is ok in 2.6.39

I have a custom Linux appliance with a 100M ethernet port. Under the 2.6.39 kernel, networking was never an issue. Autonegotiation worked just fine, as did network transfers. Now, with the newer ...
-1
votes
1answer
60 views

Networking service not responding [closed]

Networking is going down on some of our machines. This is happening very randomly. Restarting networking is fixing the issue. I found the following in the kernel logs: Mar 19 18:19:05 <host> ...
-1
votes
1answer
171 views

Ethernet Bridging With USB-to-Ethernet Adapter

I have a USB-to-ETHERNET adapter (CP-USB-RJ45M) with which I am trying to create an ethernet bridge in CentOS Linux for ip-forwarding within a private LAN test network. I modified my /etc/rc.local ...
1
vote
1answer
69 views

Why do network cards seem to work fine without firmware in Linux?

I have computers with Intel and Realtek Ethernet cards, and I keep forgetting to install the linux-firmware packages when I put Debian on them. I can see messages in syslog telling me that the ...
0
votes
0answers
134 views

Error: NETDEV WATCHDOG: eth0 (igb): transmit queue 2 timed out

Today, suddenly one of the network interface went down with kernel log saying: [5859423.746817] NETDEV WATCHDOG: eth0 (igb): [5859423.746818] Modules linked in: ipmi_si [5859423.746842] Pid: 0, comm: ...
0
votes
1answer
99 views

Ethernet is taking very long time to recover after switching loop

Problem generation is very simple like jamming a network without STP ;-) Ok, so steps of creating my problem is given as follows: Ping Device A from Device B. Reply is coming. Generate a network ...
0
votes
1answer
113 views

Unable to set initcwnd on a Hetzner server

We just ordered a bunch of Hetzner EX40SSD servers with the minimal Debian install image that they provide and everything is just fine except that looking at tcpdumps for fine tuning the network from ...
0
votes
1answer
255 views

Linux network interface broadcast statistics

I am looking for a way to see the number of Ethernet broadcast frames transmit/received by the network interfaces. I am familiar with many Linux commands,procs and options to get interface statistics ...
3
votes
1answer
491 views

OpenVPN to host tap device having very large MTU

Question What is the minimum set of server and client configuration directives that I need in order to satisfy the following conditions? Virtual layer 2 ethernet network that will not be bridged ...
2
votes
0answers
541 views

10GbE be2net low pktgen performance

I am testing the network performance of two workstations, each having 2.4GHz Xeon quad core processors and NC550SFP PCIe Dual Port 10GbE Server Adapters, linked back to back. I've checked the ...
0
votes
2answers
97 views

Switch between network configurations via command line in fedora 17

I have two different setups I use on my work laptop; one enables synergy over an ethernet ssh tunnel with my work computer on the local network, and the other opens an HTTP tunnel to my work computer ...
1
vote
2answers
226 views

Tunnel Ethernet Packets over SSH

I have two machines. My laptop and a machine in the local intranet. This machine has next to the network device (for the intranet) a second network card. I want to send raw ethernet frames out of this ...
0
votes
1answer
90 views

Multiple ethernet interface on one ethernet card

First I must say that I am new in linux and maybe I will ask trivial question. My job is to create 8 ethernet interface to be visible in kernel, but all of them should send and receive data through ...
3
votes
2answers
276 views

How can I make a secondary NIC port “eth0”?

I am using CentOS 5.9. One of my servers recently had a malfunctioning NIC port. The software running on the server was hard-coded to use eth0. The other physical NIC ports were fine and unused. The ...
2
votes
2answers
207 views

High number of ethernet errors. Tool for testing the ethernet card?

have an Asus Sabertooth X79. I often get corrupted files. I checked the RAM, but memtest finds no errors. To avoid the possibility of disk errors, I tried copying files to tmpfs. If I copy from the ...
0
votes
0answers
178 views

linux ethernet card ping problems?

I have a very strange problem with my ethernet card. Here is ethernet card details: description: Ethernet interface product: RTL8169 PCI Gigabit Ethernet Controller vendor: Realtek ...
4
votes
1answer
298 views

Is is possible to put a tagged vlan on one physical interface on a Force10 S50N switch?

I servers that have a shared ethernet port for IPMI and the first NIC. They have 4-1GbE nics. I would like to bond the nics via LACP while still being able to access the IPMI over a tagged vlan only ...
2
votes
2answers
2k views

How to change 'Advertised pause frame use' and autonegotiation setting on gigabit NIC

I'm investigating some poor nfs performance on a new server, as compared to an old server. Both the old and the new server are nfs clients, and they connect to the same exact NetApp nfs server. My ...
-1
votes
1answer
198 views

How can I 'link' one ethernet Network with a Wireless Network? (Linux) [closed]

I have: WiFi network with SSID=Network1 (running its own DHCP Server and connected to internet). Computer1 with 1 ethernet interface and 1 WiFi interface. Computer2 with ethernet interface. My ...
3
votes
3answers
7k views

What are the differences between channel bonding modes in Linux?

Under Linux you can combine multiple network interfaces into a "bonded" network interface to provide failover. But there are several modes, some of which do not require switch support. I'm not ...
0
votes
2answers
637 views

ifdown em1 Users cannot control this device. Allow users to control em1 device

I want to allow users to control the em1 device in Linux: When I run this command: ifdown em1 em1 is the embedded ethernet card 1, I want the user to be able to turn off the ethernet card. On ...
2
votes
2answers
3k views

Fedora 17 ifconfig eth0 returns an error message, why did linux change eth0 to em1?

I have a fresh install of Fedora 17 installed, 64 bit. Everything works flawlessly, It connects to the internet automatically when I plug in the internet cable. So I'm kind of confused when I ...
3
votes
1answer
120 views

Two network cards latency

I'm trying to setup a network architecture where one network is a low-latency low-bandwidth tcp control system (GBit), the other is a high-bandwidth udp (maybe tcp) network that could get saturated ...
0
votes
0answers
571 views

Trying to make USB-to-Ethernet adapter work on CentOS 5

I have a SR9600 USB-to-Ethernet adapter and, when plugging it on a Dell server running CentOS 5, the lsusb listing doesn't even change -- nothing at all appears in dmesg. But the USB port on that ...
-2
votes
2answers
156 views

Transparent round-robin scheduling of multiple network interfaces without bonding

I have a server communicating with a cluster of machines and the bottleneck is the network bandwidth. The good news is there are 2 interfaces, while the server can only make use of one. Without ...
3
votes
2answers
2k views

How do I dynamically obtain IP addresses for VLAN interfaces?

I have an Ubuntu machine on which I have created four VLANs, namely eth0.100 ,eth0.200 , eth0.300 and eth0.400. I want to dynamically obtain the IP addresses using the DHCP server. It should provide ...
1
vote
2answers
1k views

interrupt coalescing for high bandwidth packet capture?

I have an application which does packet capture from an ethernet card. Once in a while we see packets dropped (we suspect due to the buffer in the network card or kernel being overrun). I am trying ...
1
vote
3answers
432 views

Get the MAC addresses of all the machines connected to a LAN when NO machines have got an IP address yet

Here is the real scenario. I have say 4 machines not having any IP address yet connected to a switch. In one of the machines (OS=CentOS), I would install a DHCP server and would provide the other ...
0
votes
3answers
3k views

Failed to bring up eth1 in a dual ips solution in ubuntu

I'm using ubuntu 12.04. I tried to assign two ips to two ethernet cards in my server. The content of /etc/network/interfaces is like this: auto lo iface lo inet loopback auto eth0 iface eth0 inet ...
4
votes
1answer
4k views

Where are ethernet errors logged?

Munin is showing me a graph like this: During that spike, I was unable to access my server through the eth0 port (I could access it through my IPMI port). I'm trying to figure out what happened, ...
0
votes
2answers
132 views

Ethernet fails just for seconds

I have a clearos gateway linux working as gateway. I have some problems with the conectivity, everything works great but for a few seconds internal ethernet stops working. After 5-10 seconds, it works ...
2
votes
1answer
833 views

Linux server equivalent of Cisco Discovery Protocol (CDP)?

I am wondering if there are any Linux tools out there which might aid in identification of hosts directly connected to each other (much like Cisco Discovery Protocol on switches)? I have found ...
2
votes
1answer
476 views

bonding driver in centos 5.5,mode balance-rr not work

i've creat a bonding interface in centos 5.5,i chose mode balance-rr,using slave eth6 and eth7,and the link of eth6 and eth7 is ok,here is the configuration file: [root@50:B3:42:00:00:A3 ...
3
votes
1answer
2k views

Ubuntu Linux - two interfaces, same subnet, different vlan - MAC/ARP issues

I'm attempting to setup a server that needs to have interfaces on the same IP subnet, but different VLANs: eth1.102 Link encap:Ethernet HWaddr 00:50:56:b1:00:0f inet addr:10.1.1.6 ...
0
votes
1answer
120 views

Linux network adapter keeps changing settings

I'm running CentOS 5 and noticed for the past week that eth0 settings keep changing and I have to reset them. Any ideas what it might be or where I need to start?
2
votes
2answers
267 views

Is it possible to wake a computer connected directly to its NIC?

If two computers are connected by ethernet directly (ie, with no router between them) can one computer wake the other using the magic packet? I ask because it's not working for me and I'm not getting ...
2
votes
2answers
572 views

Ethernet over IP

I need to merge two L2 broadcast domain into single domain and I have to do this over unmanaged by me L3 IP network. All that I could find is vtun utility for linux. Which software&howto you can ...
1
vote
1answer
878 views

QLogic QLE8152 won't link up with a fiber loop

I have a Dell R710 running Debian Linux 6.0 (Squeeze). I installed a QLogic QLE8152 CNA in the PCI-E riser today and I have been trying to get the CNA's ethernet layer to come up after I put a fiber ...
0
votes
1answer
348 views

How to determine the interface name for 2 Ethernet adapters with 8 ports?

I have 2 Ethernet adapters on a 2U server, each of them has 4 ports, for a total of 8 ports. Is there a way to find out the interface name(eth0, eth1 ...eth7) for each port without connecting to a ...
2
votes
1answer
336 views

Multi-NIC Linux machine's NICs are responding to each other's ARPs regardless of arp_filter setting

I have an old Linux machine running a 2.4.37 kernel. In the machine are two NIC cards both on the same network with different IPs. For some testing, we want each IP's traffic routed through that NIC, ...
1
vote
4answers
138 views

Linux - Is there a way to determine what mac addresses an interface has seen traffic from?

Yes, I know about ARP but that relies somewhat on IP layer connectivity in that the remote system must be configured with an IP on a recognized subnet. Is there any way to just dump off what mac ...
1
vote
3answers
1k views

interface id for ethernet card

My PC (CentOS)has one ethernet card 1, linked to the internal company network for internet surfing etc., and another ethernet card 2, linked with an embedded device for programming. Each time, when ...
19
votes
3answers
735 views

Best way to get the MAC of eth0?

Is there a more efficient way to retrieve the MAC address of a NIC in Linux? This works: ip link show dev eth0 | awk ' /link\/ether/ { print $2 }' but can it be found via something like: cat ...
0
votes
5answers
206 views

Break Network between two hosts without pulling Cable

I have two Linux hosts HOST1 and HOST2 connected by cross cable. How I can break the network between then without breaking the physical wire (I don't have access). If i do: HOST1# ifconfig eth0 ...
1
vote
2answers
397 views

Using eth0 and ppp interfaces in a interchangeable mode

I've a Debian system without UI, with a GPRS modem attached to it. Now, this system is connected with ethernet through a standard cable. I want to obtain a configuration that allows the computer to ...
2
votes
3answers
395 views

Performance penalty of multiple IP's per network interface

How can I measure the performance penalty of a network adapter that is configured with 2 IP addresses per eth0 ? The network card has 2 physical interfaces (ports): eth0 and eth1 with only eth0 ...
0
votes
2answers
2k views

Linux is not sending arp request

We have a local network that is connected to internet through linux gateway. There are about 50 workstations in LAN. We recently started observing a problem that gateway sporadically stops responding ...
2
votes
1answer
2k views

Ethernet link dropping out consistantly (CentOS 5.5 / Dell 2950)

A few days ago the internal interface on one of my backup servers went down, and I've not been able to get it to work correctly since. In dmesg, I'm seeing: ADDRCONF(NETDEV_UP): eth0: link is not ...
2
votes
2answers
2k views

ethernet smp_affinity vs /proc/interrupts vs /sys/class/net/ethX/device

My goal is to configure our CentOS ("free" RHEL) 5.x servers for custom low-latency network programs. I would like to experiment with binding ethernet NIC interrupt handling to the same CPU on which ...