Posts Tagged ‘tcp/ip’
April 3rd, 2009 | 
Author: This post will explain hot-to configure a unique IP Address on multiple NICs (Phisical or Virtual) on Debian GNU/Linux (with a 2.6 kernel).
This post assume you have a 192.168.0.0/24 network and that you want to assign 192.168.0.10/24 to your system.
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Ethernet bonding refers to aggregate multiple ethernet channels together to form a single channel. This is primarily used for redundancy in ethernet paths or for load balancing. This page refers to ifenslave mode in particular to configure ethernet bonding on Linux systems, and so doesn’t limit itself to discussion of 802.3ad Trunk Aggregation.
I’ve used the following modes a lot of time under Debian or Ubuntu and on Open-E.
This post will explain hot-to configure a unique IP Address on multiple NICs (Phisical or Virtual) on SuSE Linux Enterprise Server (9 or 10).
This post assume you have a 192.168.1.0/24 network and that you want to assign 192.168.1.1/24 to your system.
This post will explain hot-to configure a unique IP Address on multiple NICs (Phisical or Virtual) on RedHat Linux (or Fedora).
This post assume you have a 192.168.1.0/24 network and that you want to assign 192.168.1.1/24 to your system.
This post will explain hot-to configure multiple IP Address on ONE nic (Phisical or Virtual) on RedHat Linux (or Fedora).
This post assume you have a 192.168.1.0/24 network and that you want to assign 192.168.1.1/24 and 192.168.1.2/24 to your system.
The following is some Networking Stuff about VMware ESX networking.
You could also find all these information on VMware WebSite but I like to keep some info also here for personal quick reference.
Virtual Ethernet Adapters
There are three types of adapters available for virtual machines :
- vmxnet is a paravirtualized device that works only if VMware Tools is installed on the Operating System. This adapter is optimized for virtual environments and designed for high performance.
- vlance emulates the AMD Lance PCNet32 Ethernet adapter. It is compatible with most 32-bit guest operating systems and can be used without VMware Tools.
- e1000 emulates the Intel E1000 Ethernet adapter and is used in either 64-bit or 32-bit virtual machines.
There are two other virtual adapters that are available through VMware technology. Vswif is a paravirtualized device similar to vmxnet that is used by the VMware ESX service console. Vmknic is a device in the VMkernal that is used by the TCP/IP stack to serve NFS and software iSCSI clients.
Virtual Switches
VMware technology includes virtual switches that you can build on demand at run-time to provide different functions, including:
- Layer 2 forwarding.
- VLAN tagging, stripping and filtering.
- Layer 2 security, checksum and segmentation offloading.
This modular approach reduces complexity and maximizes system performance, VMware virtualization technology loads only those components it needs to support the specific physical and virtual Ethernet adapter types used in the configuration. Additionally, the modular design enables VMware and third-party developers to incorporate new modules to enhance the system in the future. Up to 248 virtual switches can be created on each VMware ESX host. Following are important features of virtual switches:
- Virtual ports: The ports on a virtual switch provide logical connection points among virtual devices and between virtual and physical devices. Each virtual switch can have up to 1,016 virtual ports, with a limit of 4,096 ports on all virtual switches on a host. The virtual ports provide a rich control channel for communication with the virtual Ethernet adapters attached to them.
- Uplink ports: Uplink ports are associated with physical adapters, providing a connection between the virtual network and the physical networks. They connect to physical adapters when they are initialized by a device driver or when the teaming policies for virtual switches are reconfigured. Virtual Ethernet adapters connect to virtual ports when you power on the virtual machine, when you take an action to connect the device or when you migrate a virtual machine using VMware VMotion. A virtual Ethernet adapter updates the virtual switch port with MAC filtering information when it is initialized or when it changes.
- Port groups: Port groups make it possible to specify that a given virtual machine should have a particular type of connectivity on every host, and they contain enough configuration information to provide persistent and consistent network access for virtual Ethernet adapters. Some of the information contained in a port group includes virtual switch name, VLANIDs and policies for tagging and filtering, the teaming policy and traffic shaping parameters. This is all the information needed for a switch port.
- Uplinks: With VMware technology, uplinks are the physical Ethernet adapters that serve as bridges between the virtual and physical network. The virtual ports connected to them are called uplink ports. A host may have up to 32 uplinks.
REFERENCE: http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf
Hope this help
Bye
Riccardo
Hi, this is a simple doc who explain the main TCP/IP communications established in a VMware Virtual Infrastructure.
Hope this help to open “all” the rights ports on your firewalls.
Bye
Riccardo
Hi all,
few days ago, I’ve must edit some TCP/IP settings on a Linux box.
Expecially settings regarding Keep Alive.
These settings can be found on /proc/sys/net/ipv4 .
Here are the details of few of them.
tcp_keepalive_time : This value shows how often tcp sends out KEEPALIVE messages. The default is 7200 (2 hours).
tcp_syn_retries : Number of times initial SYNs for a TCP connection attempt will be retransmitted. This value should not be more than 255. This is only the timeout for outgoing connections.
tcp_retries1 : This defines how often an answer to a TCP connection request is retransmitted before it gives up. This is only the timeout for incoming connections.
tcp_fin_timeout : The length of time (in seconds) TCP takes to receive a final FIN before the socket is always closed. This is required to prevent DoS attacks.
tcp_keepalive_probes : Number of KEEPALIVE probes tcp sends out, until the server decides that the connection is broken.
You can change the values by updating the files in /proc/sys/net/ipv4 or sysctl .
To make it permanent add it to /etc/sysctl.conf.
Below are the default values of these parameters, you can change these values to suite your requirement.
# vi /etc/sysctl
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_time = 7200
net.ipv4.tcp_syn_retries = 5
#
Hope this help.
Bye
Riccardo
I am looking for a hardware solution that supports sharing USB over IP (aka USB Servers).
Here is information about 5 hardware devices, that I obtained from their websites:
Keyspan – model U2S-2A (2-port)
- supported OS: WinXP or Vista (32bit), MacOS X v10.3.9 or greater
- supports 8 connections???
- does not currently support attachment of USB hubs (expected in future firmware)
- PROS: claims it can support any USB device that is NOT an isochronous device or an ILOK dongle by PACE
CONS: Limited documentation for this model
Silex technology – model SX-2000U2 (1-port)
- supported OS: W2K, WinXP, Vista, MacOS X
- supports 15 connections (incl. hub)
- PROS: Frequent firmware updates, supports more connections
- CONS: only one port
Lantronix – model UBox 2100 (2-port)
- supported OS: W2K, WinXP
- supports 8 connections???
- Isochronous audio/video support
- PROS: First and currently only to claim to support isochronous transfers
- CONS: Limited documentation on this model
Belkin – model F5L009 (5-port)
- supported OS: WinXP,Vista (incl 64bit), MacOS 10.4 (beta)
- supports 16 connections
- PROS: Sexy looking, supports more connections, comes already with 5 ports, claims it may supported isochronous transfers in future update
- CONS: reports suggests poor performance with drives, but this may be a perception issue
IOGear – model GMFPSU22W6 (2-Port)
- supported OS: W2K, WinXP
- supports 5 connections
- PROS: supports a storage server mode, allowing multiple user access
- CONS: don’t have any info yet on this model
I am only comparing USB2.0 hi-speed (upto 480Mbps) models, even though most of these mfg have full-speed (upto 12 Mbps) models too. All seem to sell for approximately $130 and support common features like WLAN compatible, printer auto-connect share, 500mA power per port. Plus some mfg are looking to add more features in future firmware and driver releases. Early testing suggest that these units perform marginally better than USB1.1 devices, due to the network connection (latency), but I am curious about the performance of the Lantronix model that claims to support isochronous transfers.
