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Questions tagged [loopback]

In TCP/IP a loopback device is a virtual network interface implemented in software only and not connected to any hardware, but which is fully integrated into the computer system's internal network infrastructure. Any traffic that a computer program sends to the loopback interface is immediately received on the same interface.

In TCP/IP a loopback device is a virtual network interface implemented in software only and not connected to any hardware, but which is fully integrated into the computer system's internal network infrastructure. Any traffic that a computer program sends to the loopback interface is immediately received on the same interface.

A loopback interface has several uses. It may be used by network client software on a computer to communicate with server software on the same computer, namely on a computer running a web server, pointing a web browser to the URLs http://127.0.0.1/ or http://localhost/ will access that computer's own web site. This works without any actual network connection–so it is useful for testing services without exposing them to security risks from remote network access. Likewise, pinging the loopback interface is a basic test of the functionality of the IP stack in the operating system.

Source: wikipedia

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CentOS - massive usage on loopback interface

I have a CentOS installation which is running fairly smoothly. Today I ran ifconfig mainly to see what sort of usage has been coming across the ethernet interface, and to also check my link speed. This is what I ended up seeing for the loopback…
Matthew Iselin
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Is there a way to add multicast to loopback interface on a kubernetes pod?

Using an in-prem kubernetes installation on baremetal (Ubuntu) servers, installed with kubeadm. Kubernetes version is 1.25.3 Need to have multicast on a pod's loopback for the automated tests running, and I didn't find a way to get it. For a…
Mikha
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Gigabit RJ45 loopback not working (100 Mbps ok)

I made myself a loop back plug as per When I plug it into a 1Gbps port on 100/1G switch the port does not light up. 100 Mbps port on 100 Mbps switch lights up no problem. The obvious problem could be that I crimped the cable wrong, but now I'm on…
user3280964
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Does DPDK/RDMA between 2 machines gives lower latency than local host ping

I know loopback will go through the kernel network stack until reach IP layer, including syscall overhead and some memory copy overhead. DPDK and RDMA use different technology to avoid these. So let's say I have two machine connected by dpdk/rdma,…
Liang Mury
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How to assign an additional IP to loopback

I have a few docker containers which are supposed to access a shared PostgreSQL running on the Gentoo host. This works well if the dockerized apps connect to the database using the public IP of the host. However, I'd like to decouple things a little…
svoop
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two tap device connect each other in same pc

What I want to implentent is something like below. 192.168.1.1 192.168.1.2 +--------+ +----------+ +-----------+ +---------+ +---------+ | APP0 +<---->+ tap0 …
randomeval
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changing netmask of loopback interface

I can change netmask of loopback inteface (usually lo interface has 127.0.0.1/8): pi@raspberrypi:~ $ ifconfig lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 …
mastupristi
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How can I capture traffic for a daemon listening on a cloned loopback IP address?

I have a daemon listening on a virtual IP address attached to a cloned loopback interface (lo1) on FreeBSD 11.x. Inbound traffic for that daemon could arrive on several different physical interfaces, however running tcpdump on loopback only shows…
Alnitak
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iptables loopback opens all ports

I have a strange problem with iptables and my loopback interface. ifconfig says: lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 for both ipv6 and ipv4…
Tim Altgeld
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Loopback interfaces is not pinging on both pcs for packet tracer

I am trying to ping my isp ip address (aka loopback 1) and loopback 10 to PC1 and PC2. Whenever I ping both ip addresses and default gateway from pc1 to pc2 it works. However, when I'm trying to ping my isp ip addresss (1.1.1.1) and loopback 10 ip…
Kevin
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How can I count / view all fast-path sockets on windows server?

In case you're not familiar, fast path loopback sockets: https://blogs.technet.microsoft.com/wincat/2012/12/05/fast-tcp-loopback-performance-and-low-latency-with-windows-server-2012-tcp-loopback-fast-path/ How can I count how many connections of…
Ronen Ness
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Windows Loopback adapter not participating in local network

I have created a Windows loop back adapter with 'Obtain IP address Automatically' enabled. ipconfig /all Ethernet adapter LL Address: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft Loopback Adapter #3 …
Programmer
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Kubuntu 17.04 on VM: loopback interface routed "outside"

Disclaimer: Yes, I know my problem description might be not very accurate and my terminology as well. Can not change that since I am new to this topic and do not know it yet. But I apprechiate suggestions how to improve my question. My problem: I…
Michael
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Server send TCP ACK with wrong number after receiving SYN

I have a client establish new TCP connection then sends request to a server per second. Both client and server are on the same linux box (via loopback interface). The client periodically reports socket error. After digging the network packets, the…
petertc
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Two loopback adapters communication in windows 7 or 8

Once our development systems are upgraded from windows XP to windows 7, my debug setup has stopped working. Steps followed in original setup (Windows XP): Add two loopback adapters Assign ipv4 172.16.16.1 to one adapter and 172.16.24.1 address to…
Shreyans
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