Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
Hello,
In a Virtualization environment, for some reasons, host NIC must be in promiscuous mode, but I don't like my Linux VM that using that NIC working in promiscuous mode. Any command that could block this mode in my Linux VM? Is it OK?
Distribution: Ubuntu based stuff for the most part
Posts: 1,177
Rep:
The VM will need that to work with most networking. If you can install an second NIC in the system, then you can set that aside for the VM to use.
Read up on how the VM tools you are reading do networking as it varies between them a bit.
Distribution: Ubuntu based stuff for the most part
Posts: 1,177
Rep:
The VM will need that to work with most networking. If you can install an second NIC in the system, then you can set that aside for the VM to use.
Read up on how the VM tools you are reading do networking as it varies between them a bit.
Hello,
In a Virtualization environment, for some reasons, host NIC must be in promiscuous mode
In non-promiscuous mode, an ethernet NIC only accepts frames that are destined to its own MAC address, or broadcast frames. Since the MAC addresses of the VMs are different, traffic destined to the VMs would be blocked if the VM host's NIC were not promiscuous.
Quote:
but I don't like my Linux VM that using that NIC working in promiscuous mode.
You can't always get what you want.
Quote:
Any command that could block this mode in my Linux VM? Is it OK?
Sure.
Code:
ip link set [interface] promisc off
You seem to be confusing the host's NIC and the VM's NIC. Only the host's NIC needs to be promiscuous (except for special cases like nested virtualization perhaps).
Last edited by berndbausch; 10-09-2020 at 05:44 PM.
In non-promiscuous mode, an ethernet NIC only accepts frames that are destined to its own MAC address, or broadcast frames. Since the MAC addresses of the VMs are different, traffic destined to the VMs would be blocked if the VM host's NIC were not promiscuous.
You can't always get what you want.
Sure.
Code:
ip link set [interface] promisc off
You seem to be confusing the host's NIC and the VM's NIC. Only the host's NIC needs to be promiscuous (except for special cases like nested virtualization perhaps).
If promiscuous mode is ON then can it make any security problem?
To disable promiscuous mode on the physical NIC, run the following command on the XenServer text console # ifconfig eth0 –promisc.
Run the ifconfig command again and notice that promiscuous mode is now disabled.
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.
How to block Promiscuous mode?
