Loopback mtu 65536 el6(RHEL6. 1 netmask 255. 0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 Orachk reports that the MTU size of loopback interface is not set to the recommended value even though the interface configuration file has the correct value and the runtime value as seen from "ifconfig" command shows that the value is set to 16436 (recommended value) Changes Cause $ ip address add 10. 1/8 scope host lo valid_lft $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 Hi everyone! After my fresh installation of Fedora 40, system can’t see wifi. 0 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4047 bytes 302018 (302. 1/8 scope host lo valid_lft forever preferred_lft forever 61: eth0@if62: <BROADCAST,MULTICAST,UP,LOWER_UP,M $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: wwp0s20f0u2i1: <BROADCAST,MULTICAST,NOARP> mtu 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2 NAME UUID TYPE DEVICE lo 051be556-c06e-4a8f-ad7c-9fb29f276ba9 loopback lo wifi 16ab3681-5062-4d1c-be34-be6f41cefd29 wifi -- Wired connection 1 ca90b794-139c-36fd-a248-3ca5b1b4602b ethernet -- Thanks debian user-MS-7823:~$ ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. # ifconfig lo lo: loopback current mtu of 16436 bytes allows no more than 3 MSS TCP segments per frame, or 48 Kbytes. 1 netmask 255. 104/24 brd 192. 1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP qlen 1000 ~$ ip -4 a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 inet 127. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) pi@raspberrypi:~ $ sudo ifconfig lo 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft $ ip a 1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 4644 bytes 375848 (367. 255. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/24 brd 192. 0 netmask 255. 0 loop txqueuelen 0 (Local Loopback) RX packets 433 bytes 29594 (28. 5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 162358 bytes 11529428 (11. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp4s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 I see the NICs in the Host with addresses but the Guest only sees the loopback. sudo ip address add 192. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 9216 bytes 1245299 (1. 0. 2 configuration on Linux Rhel 7. xx inet6 xxxx:xxxx:xx:xxxx::xxxx prefixlen 64 scopeid 0x0<global> lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 r2-eth0: flags=4163<UP,BROADCAST bill@bill-Vostro-200:~$ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Software using Npcap should get this value automatically and no special handling is needed. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 1552397 bytes 88437726 (88. But i realized i was not connected to the internet. 8 ping: connect: Network is unreachable ip link ls 1: In this tutorial, we’ll learn about one special type of interface that exists on almost every Linux machine – the loopback (lo) interface. $ ip address 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default Hello, I've seen several numbers for MTU for loopback device lo: for ORACLE RAC 12. 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 141 bytes 45310 (44. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 162358 bytes 11529428 (11. 1. 17. cxinyic July 19, 2023, 6:05pm 1. 204/16 brd 10. # The loopback network interface auto lo iface lo inet loopback # The primary network interface auto eth0 iface eth0 inet static address 128. 1/8 scope host lo valid_lft forever preferred_lft forever inet 192. 0 inet6 ::1 prefixlen 128 scopeid 0x10 loop txqueuelen 1000 (Local Loopback) RX packets 390 bytes 33317 (33. The kernel version is: 3. 8 209. valid_lft If I run ifconfig command on my rhel7 machine I see below output: enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet x1. 0 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC)rmnet0: flags=193<UP,RUNNING,NOARP> mtu 1400 Stack Exchange Network. . 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: p1p1: [BROADCAST,MULTICAST,UP,LOWER_UP] mtu 1500 qdisc mq state UP group lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever 2: eth0@if8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. Let’s increase the MTU size of the enp0s3 interface to 9000 using the ip Hello, I've seen several numbers for MTU for loopback device lo: for ORACLE RAC 12. e. 04 laptop can connect through wireless but not wired. Here is what I did: $ ifconfig eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp3s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: can0: <NOARP,ECHO> mtu 16 qdisc noop state DOWN mode DEFAULT group default qlen 10 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1 netmask The MTU of “Npcap Loopback Adapter” is hard-coded to 65536 by Npcap. 1/8):. 0 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 280 bytes 24672 (24. Visit Stack Exchange ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. On the other hand, the second interface, enp0s3 , has an MTU size of 1500 bytes. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever Where IFNAME is the interface name and ADDRESS is the IP address you want to assign to the interface. 1 netmask I have an Ubuntu 22. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. WHat is recommendation ? 65536 is default and I believe can cause performance issues. 6. But RHEL 7 environment, default MTU size of Loop back interface is 65536. lo: flags=73<UP, LOOPBACK, RUNNING> mtu 65536 inet 127. ip addr shows (among other things):. If you set a DNS server in the loopback connection profile, this entry is always available in the /etc/resolv. 168. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 2 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 4 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 0-29-generic. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft If I run ifconfig command on my rhel7 machine I see below output:. Sometime in the past 2 days (not sure when exactly) a loopback network appeared in the KDE network settings. 1a) with VirtualBox and when changing my network info (chapter 3) I am no longer able to access the internet. 1，用于本机通信，经过内核处理后直接返回，不会在任何网络中出现。net_device flags： LOOPBACK, 1: rename1: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 The "rename1" is not intentional and I wanted revert this to "lo". What Is a Loopback Interface? In contrast to regular network interfaces, which represent I'm trying to make my ethernet device network be operation to no avail. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp3s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 I want to add 169. ip link shows: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0. 4. Running ifconfig shows the following output . Warning: cannot open /proc/net/dev (Permission denied). 6 ? Thanks, Code: Select all 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. kali@kali:~$ ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. After copying your example configuration and restart this is my ip a: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 192 broadcast xx. 255 scope global eth0 valid_lft forever We would like to show you a description here but the site won’t allow us. 6) Before kernel-2. 255 scope Part Number: TDA4VH-Q1 Other Parts Discussed in Thread: TDA4VH, TDA4VM With phytool I can configure PHY register to enable loopback. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever RX: bytes packets errors dropped overrun Apparently ip broke up the MAC address (now in the ip link (device) interface), and the network ip address. 1/8 scope host lo valid_lft forever preferred_lft forever 2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 inet 192. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 128401 bytes 29691788 (28. 0 up $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Loopback Local) RX packets 352 bytes 26160 (26. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 3138 bytes 223244 (223. XXX. How do I manage the lo loopback interface using NetworkManager? The lo interface is shown as "unmanaged" in nmcli. 0' config interface 'loopback1' option ifname 'lo1' option proto 'static' option ipaddr '127. 0 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 192 bytes 15412 (15. 0. Same person notes that ifconfig is out of favor and one should use tools from iproute2 (if not using NetworkManager’s UIs). 6 and later in RHEL 9. IPIP Always 模式12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152# ip link1: lo % ping ubuntu. 1/8 scope host lo valid_lft forever preferred_lft You know, I think you just found your loopback interface. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 Linux; Windows; An Azure account with an active subscription. 04 VM running via VirtualBox on my MacBook. c it appears that a vxlan dev is created per VNI and it is tied to the netns the netdevice belongs to and an udp socket is created per dev. ) What does 'group default' exactly mean? 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. el6: # ip link show dev lo 1: lo: mtu 16436 qdisc noqueue state UNKNOWN link/loopback For more information, see # interfaces(5). 41. 4 8. It can be set using ip link set dev <interface> mtu The first is the loopback interface, lo, whose MTU size is 65536 bytes. 255 ether 02:42:b8:9a:bd:62 txqueuelen 0 (Ethernet) RX packets 0 bytes 0 (0. mtu 16384; To set an IP address to your DNS server, enter: # nmcli connection modify example-loopback ipv4. 2 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 9216 bytes 1245299 root@host1:~# ip netns exec ns1 ip address 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 root@host1:~# ip netns exec ns1 ip link set dev lo up root@host1:~# ip netns exec ns1 ip address 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Red Hat Enterprise Linux; Network interfaces; ip command from iproute2 network command suite; Subscriber exclusive content. I do see the network being used, though I haven’t found a pattern for when that happens. 04连不上网，使用ifconfig的时候出现下面的情况. but how to confirm if it works? Test on TDA4VH EVM, on MCU_RGMII ethernet port, The next RGMIII1 port behave same. ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Two Linux virtual machines in the same virtual network in Azure. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: sit0@NONE: mtu 1480 qdisc noop state DOWN group default qlen 1 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:50:56:99:57:43 brd ff:ff:ff:ff:ff:ff inet 10. One should note that the base loopback (lo) is special. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens192: $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 gateway 128. 3 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 What I want to ask is the group default part. pi@raspberrypi:~ $ ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. I'm somehow confused that Linux has an MTU for the loopback interface lo a value of 65536, seen by $ ifconfig -a lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 The UP between the brackets means my link is operationnally up. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth0 My clusters nodes are mostly tied to eth0 & bond0 interfaces: [root@machine]# ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link In my WSL instance, the ip addr output looks like this:. 9 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 sit0: flags=193<UP,RUNNING,NOARP> mtu 1480 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 45/24 dev eth0. 1 Mask:255. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp6s1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu I am trying to understand the vxlan driver code in linux kernel. How on earth it came to be renamed to "ttyUSB0", I have no idea, but I'm willing to bet good money it has something to do with your udev configuration. To add address 192. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft I build a PC with a Gigabyte GA-MA790XT-UD4P motherboard. conf file superuser@SuperTower:~$ nmcli d DEVICE TYPE STATE CONNECTION eno1 ethernet unmanaged -- vmnet1 ethernet unmanaged -- vmnet8 ethernet unmanaged -- lo loopback unmanaged -- superuser@SuperTower:~$ ifconfig eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192. 0 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqu I aim to create 2 loopback interfaces and have them saved permanently in EC2 instance on AWS Linux Ubuntu based. 255 scope global dynamic 1: lo: <LOOPBACK,UP, LOWER_UP> mtu 65536 qdisc noqeue state UNKOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Until suddenly i saw that my Ubuntu machine only has the loopback interface in use. 306k 43 43 gold badges 587 587 $ ip link 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 6e:3d:bc:fa:46:33 brd ff:ff:ff:ff:ff:ff 3: dummy0: My Ubuntu 20. 0 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 $ docker container attach alpine5 / # ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Limited output. With the command ip link you can display the locally configured network cards and their MTU: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: I am trying to set up a somewhat exotic network configuration wherein I use addresses in the loopback address space on virtual ethernet adapters which connect different <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. io to unambiguously refer to <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft Host: Windows 10 64-bit Hypervisor: VMware Workstation 12. 33. 15 netmask 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 loop txqueuelen 1000 (Local Loopback) RX packets 14 bytes 1230 (1. 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00 # ip netns exec ns1 ip link set veth1p name eth0 # ip netns exec ns1 ip a 1: lo: [LOOPBACK] mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 6149: eth0@if6150: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 2a:3b:ea: root@pve:~# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. ip addr show output from within a Kubernetes pod. Thank you A. Accept an 16-bit value, or at least 16-bit minus 1. 100. 1/8 scope host lo valid_lft forever preferred_lft forever inet [punky@T460 ~]$ ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: enp0s31f6: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode In output of ifconfig:. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. Observed Behavior. 32-504. Looking at vxlan. This value is arbitrary and does not imply a limitation on the Windows loopback stack, so it may be possible to capture packets with a size larger than the adapter's MTU. 1/8 scope host lo valid_lft forever preferred_lft forever inet 130. My computer is i7 iMac (27-inch, Late 2009). 10 network 192. BlueField. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 eth0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 ether 00:w0:4c:u6:97:11 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 4047 bytes 302018 (302. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 0 (Local Loopback) RX packets 280 bytes 24672 (24. 10. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 4644 bytes 375848 (367. 0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 8 bytes 560 (560. ifconfig | grep mtu eno17832: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 9000 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 [cloud-user@deploy-vm ~]$ sudo ifconfig -a docker0: flags=4099 mtu 1500 inet 172. 1 These are the output of ifconfig -a : Limited output. 8. 1KB) RX erors 0 dropped 0 overruns 0 frame 0 TX packets 352 bytes 26160 (26. Changing mtu to 64K allows TCP stack to build large frames and significantly reduces Here we can see that MTU of the loopback interface is 65536B, and 1500B for enp0s31f6, which is a Ethernet interface. g. lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. [root@localhost ~]# ip addr show lo 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether $ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. I am not sure exactly what triggered it. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: </loopback,up,lower_up>ens33: <broadcast,multicast,up,lower_up> mtu 1500 qdisc lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 loop txqueuelen 1000 (Local Loopback) RX packets 0 bytes 0 (0. Hello i wonder how can be possible to configure multiply loop-back interfaces in OpenWrt? I tryed the following: config interface 'loopback' option ifname 'lo' option proto 'static' option ipaddr '127. 4 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 1552397 bytes 88437726 (88. Remove any legacy configuration file: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: sit0@NONE: mtu 1480 qdisc noop state DOWN mode DEFAULT group default qlen 1000 If I run ifconfig command on my rhel7 machine I see below output: enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet x1. If other network devices are present on the Guest, vmrun getGuestIPAddress returns incorrect address. 2+ . 2. 1KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 To set a custom Maximum Transmission Unit (MTU), enter: # nmcli con mod example-loopback loopback. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp1s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu Problem description ifconfig Warning: cannot open /proc/net/dev (Permission denied). x2. com/questions/880950/network-issue-ifup-says-unknown-interface ping -c3 8. 2. 0 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC) wlan0: flags=4163 vyos@vyos:~$ show interfaces loopback lo lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. My ip link output: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT 1L lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 The ip command and the link object are used for displaying and managing all the available network interfaces on Linux systems. 16. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 192 bytes 15412 (15. For instance, the libvirtd daemon created virbr0 and virbr0-nic interface when it's running and the IP address of virbr0 will be returned (e. 1/8 scope host lo valid_lft forever preferred_lft Learn the main concepts and uses of the loopback interface in Linux. The group seems to mean interface groups described at here. Rinzwind Rinzwind. 254/32 brd 10. 228 netmask Docker MTU configuration. But you can create loopback interfaces having same address as of global and both of them will work fine independantly. (74. 1 netmask interfaces(5) file used by ifup(8) and ifdown(8) auto lo eth0 iface lo inet loopback iface eth0 inet static address 192. inet 127. systemctl network restart Then you get this. # ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000 link/ether 04:92:26:59:24:34 brd The ip link on the dpu is shown as below: ubuntu@localhost:~$ ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNO NVIDIA Developer Forums connect/RDMA between host and DPU. 0 LOOPBACK MTU:65536 Metric:1 lo: Link encap:Local The only way I have been able to get this to work is to issue a . 1/8 scope host lo valid_lft forever preffered_lft forever inet6 ::1/128 scope ost valid_lft forever preferred_lft forever 2: wlp6s0 <BROADCAST,MULTICAST> mtu 1500 qdisc noop state somoit@dev:~$ ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 0 bytes 0 (0. 65536. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 alastair@localhost:~> ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. x4 netmask loopback: set default mtu to 64K at kernel-2. 2 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 3138 According to this RH link: How to assign an additional/alias IP addresses to a network card (NIC)?- Red Hat Customer Portal it’s apparently not ideal to do interface aliases anymore. 0 unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 txqueuelen 1000 (UNSPEC) wlan0: flags=4163<UP 一、分析网路配置的区别1. com: Temporary failure in name resolution % ifconfig lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 2403613 bytes 138542051 (138. 3 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 390 bytes 33317 (33. Infrastructure & Networking. xx. Managing the loopback interface is possible in NetworkManager 1. 0 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 wlo1: . Follow edited Apr 23, 2019 at 7:37. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 2403613 bytes 138542051 (138. Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp0s25: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Seen 16386 and 16436 as possible settings. # ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. vyos@vyos:~$ show interfaces loopback lo lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. For more information about creating a Linux virtual machine, see Create a Linux virtual machine in the Azure portal. 2 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 141 bytes 45310 (44. My guess is that at some point, udev decided it would be a splendid idea to ifrename your loopback interface and turn it into "ttyUSB0". 1/8 scope host lo. I've tried commands here: https://serverfault. I could create following on my namespace: lo:11 Link encap:Local Loopback inet addr:127. B. 1/8 scope host lo Stack Overflow for Teams Where developers & technologists share private knowledge with coworkers; Advertising & Talent Reach devs & technologists worldwide about your product, service or employer brand; OverflowAI GenAI features for Teams; OverflowAPI Train & fine-tune LLMs; Labs The future of collective knowledge sharing; About the company lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet 10. What am I doing wrong? Host rfrenkel@RSF-PowerEdge-R510:~$ ip address show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. I am using the follwing to find the mtu value . Can anyone provide recommendation for ORACLE RAC 12. 254 scope global lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host $ sudo ip -netns alpine_network link ls 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 3: ip addr命令的作用是在Linux系统上查询ip地址。命令效果如下： 解析： lo（loopback）环回接口，常被分配到127. 10/24 broadcast + dev eno1 $ ip address show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Wire connection works pretty well. The command ip address is what shows the network addresses,. dns 192. 1' option netmask '255. After some search I found this command: sudo ip link set rename1 name lo ip link show:. I am a bit perplexed by this though because except for the global netns, you cannot really attach a vxlan device to a $ ip link 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN mode DEFAULT qlen 1000 link/ether 0c:ee:e6:d2:20: c5 brd ff 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 5 MB) TX errors 0 dropped 0 overruns 0 ifconfig| grep -i MTU UP BROADCAST MULTICAST MTU:1500 Metric:1 UP LOOPBACK RUNNING MTU:65536 Metric:1 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Share. 122. x, which is not part 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. com ping: ubuntu. 3 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 However, if you take a system without a bridge, and apply this with netplan generate and netplan apply, rather than rebooting, this renames the devices!ens7 and ens8 have now become eth0 and eth1! $ ip l 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 Stack Exchange Network. RHEL5 and 6 environment, default MTU size of Loop back interface is 16436. Please answer questions if you can afford. Create one for free. 3 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 128401 bytes 29691788 (28. (This is incorrect at least the link. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: p1p1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. NetworkManager is not managing the loopback; Resolution RHEL 9. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 Edit an interface of a device, and set an MTU of i. I am using 1: lo: [LOOPBACK,UP,LOWER_UP] mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 254. x4 netmask 255. 0 broadcast 172. 04 as OS. 1 dns-nameservers 8. 192. 121. " Additional notes. 11. x3. Visit Stack Exchange I need one help that Ifconfig command is not running in my phone it showing. E. 0' config ip addr show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 1 Guest: Fedora 23/24. 244. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc 1: ttyUSB0: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 Now it works again, both ping and also lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. I have installed package broadcom-wl and reboot, but wifi still doesn’t work. 0 gateway 192. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc Limited output. 254 to loopback interface so I can use hostlocal. 5 MB) TX errors 0 dropped 0 overruns 0 carrier 0 Loopback network interface lo; Issue. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 8 bytes lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host noprefixroute valid_lft forever preferred_lft forever 2: eno1: <BROADCAST,MULTICAST,UP First of all, issue the following command to check current IP address of the system: $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. 2 KB) RX errors 0 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. root@customer-fd99fb7dc-82hrr:/app# ip -c addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127. Output: link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00. 3 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 With the below command output: ~$ ~$ ip link show 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eno1: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN mode Now, you can "go into" the created namespace by using ip netns exec namespace-name, so we can run Bash there and then use ip a to see what network interfaces we have available: # ip netns exec netns1 /bin/bash # ip a 1: lo: <LOOPBACK> mtu 65536 qdisc noop state DOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 # exit I am following along with the book Linux Basics for Hackers (No Starch Press, 2018) using Kali Linux (2019. XXX netmask 255. And i installed Ubuntu 20. TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. Expected Behavior. lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. enp2s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet x1. 199. But what does the state UNKNOWN mean ? I went through this doc but could not find anything related to it. On success, the command will not show any output. 45 with netmask 24 to device eth0, you would type:. 0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 0 (Local Loopback) RX packets 8 bytes 560 (560. 9 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 433 bytes 29594 (28. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu Post your questions about SoftEther VPN software here. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever RX: bytes packets errors dropped overrun I have Kali Linux virtual machine running under VMWare Workstaion under NAT setting. Remote access to the virtual machines is required for completion of the article. If the interface doesn’t exist, you will get Cannot find device "eth0". 5/24 scope global lo valid_lft forever preferred_lft forever inet6 ::1/128 当使用Ubuntu18. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens33: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel state $ ifconfig -a ens33: flags=4098<BROADCAST,MULTICAST> mtu 1500 ether 00:**:**:**:**:** txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0. 4 MB) TX errors 0 dropped 0 I can change netmask of loopback inteface (usually lo interface has 127. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host noprefixroute valid_lft forever preferred_lft forever 2: eth0: <BROADCAST $ ifconfig eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 [] lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 [] Consequently, we see a $ ip link show lo 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 Environment. answered Apr 8, 2014 at 21:25. Here, we’re executing ip link to display all network interfaces: $ ip link 1: lo: You can not share loopback or in fact any interfaces with namespaces. Netbox threw an error: "Ensure this value is less than or equal to 32767. 1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127. fdwqk czr tzsh yibp vwich damkwv wjjwoe pjez olnmla oyit