The ethernet tag has no wiki summary.
5
votes
1answer
72 views
Can a limited broadcast packet contain destination MAC address other than FF:FF:FF:FF:FF:FF?
Can a limited broadcast contain destination MAC address other than FF:FF:FF:FF:FF:FF?
If the answer is true, could you provide an example of a protocol that uses a packet like this.
Ok, to elaborate ...
4
votes
4answers
114 views
Share one IP address with a simple router
We have just moved into a new office and have been given our 'internet connection' in the following form:
One Ethernet cable in the corner of the room
An IP address with subnet mask 255.255.255.0
...
0
votes
0answers
16 views
NIC works at 100Mb, not 1Gb - how to diagnose? [migrated]
I have a (crappy) home media server with an onboard NVIDIA MCP77 Gigabit LAN chip (under Ubuntu 10.04 Lucid). This is connected to a Virgin Media SuperHub (VMDG480) which contains a gigabit switch via ...
0
votes
2answers
59 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 ...
0
votes
0answers
36 views
How to pervent vtp updates coming from vmware to go towards switch?
To get the background of this question please follow this link
http://security.stackexchange.com/questions/14803/using-nessus-an-alien-packet-from-switch-shut-down-my-ethernet-card-completely
I have ...
2
votes
1answer
56 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 ...
0
votes
0answers
28 views
Ubuntu, my dhclient lease time is way short
I am having an issue with the lease time of my eth1 interface. A windows machine on the same network get a lease time of 5 days, while my ubuntu box switches between two ips with intervals of around ...
2
votes
1answer
55 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 ...
-4
votes
1answer
49 views
What type of connection to get for a web server [closed]
I've been doing some research about this topic but I had no luck finding my answer.
Will a 2Mbps G.SHDSL connection do the work or should I go with a 5/10/20Mbps Metro Ethernet connection?
Or am I in ...
3
votes
3answers
55 views
What could cause two devices to refuse to link?
This is a curious case where all the devices at hand will link with one another, except for two that just won't detect one another. One device is a single board computer (SBC) with a gigabit nic, the ...
0
votes
1answer
93 views
How do you explain ethernet cable problems to non networking people? [closed]
We've recently been doing a large network migration in our datacenter.
We've had a few cables in this start to deliver really bad pings (in excess of 500ms on a LAN) before they could be replaced. ...
2
votes
1answer
45 views
Ubuntu Server forgets how to connect using ethernet
I have encountered a series of errors after my Ubuntu server was restarted. It seems to have forgotten how to connect to my router as it cannot ping local or other IPs.
When I start it up it says
...
2
votes
1answer
147 views
Very low throughput on 10GbE network
I have two Linux machines, each equipped with a Solarflare SFN5122F 10GbE NIC. The two NICs are connected together with an SFP+ Direct Attach cable.
I am using netperf to measure TCP throughput ...
0
votes
1answer
39 views
Tools to inspect an ethernet packet travels through host's interfaces?
I am debugging a local ethernet connection on a Linux machine. I want to inspect the ethernet packets as they travel. in and out current machines' interfaces. I do not have a GUI on the machine. Is ...
3
votes
3answers
74 views
Is it possible to cross-connect two AUI ports without transceivers?
Many Ethernet devices predating the ubiquity of RJ45 transceivers had DB15 "AUI" ports. One is ordinarily expected to attach a transceiver for either coaxial or twisted-pair Ethernet.
Is it possible ...
4
votes
1answer
118 views
Understanding Ethernet Headers, What MTU Do I Need?
I see many articles on line stating that the overhead of Ethernet is 18 bytes (example: http://www.learnios.com/viewtopic.php?f=8&t=18887)
Looking at this wiki article ...
0
votes
2answers
135 views
Internet slowed down because of SQUID Server setup
Recently I have setup a squid server for our office.
I have computer (A) with
two ethernet cards, one for internet and the second one for local networkIt has Ubuntu server OS with squid-server and ...
4
votes
1answer
111 views
Does using VLANs in your network infrastructure cause an appreciable decrease in performance?
This is something I've never considered before and wanted the opinions of the experts. We use VLANs day in and day out for various network tasks. My modus operandi is that in general, if something ...
1
vote
2answers
175 views
Linux bonded Interfaces hanging periodically
I've several hosts that are showing problems with connectivity. When working from the command line, for example, typing is frozen for a second or so, then recovers - then it does it again.
The most ...
2
votes
4answers
113 views
Trunk fiber ports on switches
We are planning to purchase new switches for our network. We have three buildings in the same area that are all connected by fiber. Our main building is very large and needs to be connected by fiber ...
1
vote
0answers
269 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
66 views
Ethernet Device Drivers on Linux [closed]
I re-edit my first post and i will try to more explicit on my question.
I want to develop a network based on ethernet swithcs and link 2 or 3 pc's.
I will work on Linux. The ideia is to access the ...
8
votes
3answers
224 views
Cut network cables in Cisco 2960 PoE
We've a Cisco 2960e that services our VoIP phones and other things. I inherited it.
The question I have is the cut cables: there are about four network connectors that are cut about 1cm away from the ...
0
votes
1answer
59 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?
-1
votes
1answer
80 views
Can a host launch a DOS attack on Ethernet?
Here is my trail of thought:
Since Ethernet works on the principle of CSMA/CD one can possible setup a rogue host which transmits packets all the time forcing other to exponentially back off until ...
1
vote
2answers
211 views
Serial to ethernet cable: how to connect to device
How can I use a serial to ethernet cable to connect to a device: in my case a
Hp ProCurve AP?
A serial to USB or serial to serial would have been great but I found this serial
to ethernet cable from ...
2
votes
2answers
86 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 ...
0
votes
1answer
228 views
How to troubleshoot the suspected ethernet card failure [closed]
Sometimes one of the laptop when attached to the dock would drop the ethernet connection. By constantly pinging the default gateway usually there are no packet drops but sometimes, it results in ...
1
vote
2answers
166 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 ...
0
votes
2answers
62 views
2 networks with a layer 2 bridge that shouldn't be there.
I have 2 separate networks that I manage. They have a router between and layer 3 connection is working fine. Last week my DHCP servers started handing out IPs across the networks, looking around I ...
3
votes
3answers
283 views
Ethernet frames: what are the source and destination MAC addresses?
Imagine you have some network configured like this
+-----+ +------+ +------+ +-----+
|comp.|---|bridge|---|router|---|comp.|
| A |---| B |---| C |---| D |
+-----+ +------+ ^ ...
4
votes
3answers
179 views
Phantom NIC issue causing eth0/1 to drop out
We are experiencing a very strange and frustrating problem. Our company has servers here in Massachusetts, as well as in California. The issues we are seeing are only on the CA hardware. Out in CA, we ...
3
votes
1answer
172 views
Why is half-duplex mode supported for 10BASE-T and 100BASE-TX networks?
I'm currently learning about Ethernet standards, auto negotiation and duplex mismatch. That made me wondering why half-duplex operations is allowed in 10BASE-T and 100BASE-TX networks. Wouldn't it ...
1
vote
1answer
269 views
Solaris ethernet ports: e1000g1 and e1000g2 are not working
I can plumb and configure e1000g0 and e1000g3 using ifconfig, but I can't seem to make use of e1000g1 or e1000g2.
When I try ifconfig e1000g1 plumb, I get ifconfig: plumb: e1000g1: Invalid argument.
...
-6
votes
1answer
65 views
My business computer doesnt connect to any ethernet device outside business lan [closed]
My computer which i use at work is within a domain. And our internet connection is through some kind of filter. So in Internet Explorer, there is a configured lan setting. When i try to connect any ...
1
vote
4answers
330 views
Virtual interfaces with default routes
My Ubuntu Server has one physical interface eth0. I want to assign 3 ip's (different subnets) to the server. I cannot use the default virtual interface creation tools like ifconfig or ip addr add ...
-1
votes
1answer
23 views
Accessing a connected device through LAN
I have a metered APC Power Distribution Unit (PDU) which is capable of spewing out the current load, power and such information through a LAN cable. I'm connecting the cable from the PDU to a server ...
0
votes
1answer
53 views
Netgear FVX538v2 slow whene connected to Canoga Perkins N525 ETSU
First of all thank you in advance for helping me. my issue is the old network admin found a problem whene he connected the firewall and the ETSU together the through put went down to less than 1 mega ...
1
vote
1answer
223 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
234 views
Would the source and destination address in ethernet frame change?
Say there are 2 computers are connected this way in a wireless network:
Computer A -> Access Point 1 -> Access Point 2 -> Computer B
When a frame is sent from Computer A to Computer B, the frame ...
0
votes
1answer
76 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 ...
1
vote
5answers
223 views
Is a Router required to set up a network? [closed]
Is a router required to set up a network?
Suppose I have just an Ethernet wire and then I fix it up to 3 computers.
Can I then say that these computers are now in a network? If they are in a ...
9
votes
6answers
490 views
Direct ethernet link between two servers
Say I had two servers which needed super-low latency (Database, file etc.). Would it be possible to directly connect the two servers with 10GbE, so each server had 1 (in the real world it would have ...
1
vote
2answers
127 views
Two network adapters with the same ip
I have two network adapters that use the same ip range, but are different networks.
I tried this but it didn't work:
iptables -t nat -A OUTPUT -p all -d 1.2.3.0/8 -j DNAT --to-destination ...
6
votes
1answer
374 views
Ethernet interface errors
My Ubuntu servers ethernet interface that connectes to ISP's multiplexer shows errors. Here is the snapshot:
RX packets:204564288 errors:3193970 dropped:0 overruns:0 frame:3138402
...
0
votes
1answer
31 views
Two network Macs have slow internet
I work in a boutique advertising agency as a web developer. I have my own servers at home for my website.
In our office, we have 8 Macs. Two of the iMacs are against one wall with an ethernet cable ...
6
votes
1answer
94 views
What is, and what problems result in a 'carrier error'
I haven't found a really clear definition about what a 'carrier error' is within the context of the ifconfig output for a interface. I have been searching on Google and there really isn't a great ...
1
vote
3answers
99 views
Ethernet link negotiates a connection only in half duplex mode
I have a NIC which is capable of 100BaseT/Full. But it negotiates a connection only on 100baseT/Half mode. Here is the output of mii-tool:
eth0: no autonegotiation, 100baseTx-HD, link ok
The ...
1
vote
1answer
125 views
Ubuntu Server, 2 Ethernet Devices, Same Gateway - Want to force internet traffic through 1 device (or at least allow it to work!)
I have a Ubuntu 10.04 Server with 2 ethernet devices, eth0 and eth1.
eth0 has a static IP of 192.168.1.210
eth1 has a static IP if 192.168.1.211
The DHCP server (which also serves as the internet ...
0
votes
1answer
57 views
Server can only make outbound connections
My server is running Ubuntu 10.04 and is connected by ethernet to a router/modem device. The problem is that it's basically ignoring incoming connections. So I can't SSH into it or access the ...
