Questions tagged [icmp]
ICMP stands for Internet Control Message Protocol. It is primarily used by the operating systems of networked computers to send error messages indicating service status.
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Laptop replies to ping in sleep mode
Recently I got new company laptop with Windows 11 and noticed weird behaviour. When the computer is in sleep mode (screen blank, power led slowly fades in and out) the laptop still replies to network ...
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Which inbound/outbound rules are necessary for stable IPv6 connectivity in Windows 10/11?
I'm experiencing an issue with Windows 10 where IPv6 connectivity becomes unstable over time. Initially, IPv6 works as expected, but after a while, it stops working. Upon investigation, I've ...
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Why pinging device under VPN succeeds?
There are two devices connected to the same LAN network:
A with IP 192.168.1.1,
B with IP 192.168.1.0.
I connected B through VPN (WireGuard if that matters) exposed externally (B on server - BS - ...
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ICMP packet with TCP?
For some time now I have found myself interested in packet analyzing and I try to figure out all kinds of stuff that I see in network captures. I hope you guys might want to help me find out this one.
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Windows - sharing connection to WinTun interface - ping fails with protocol unreachable
I'm trying to access the network from the Windows app which creates TUN interface connection.
Windows 10 Home Edition.
TUN interface created with https://www.wintun.net/ project example code.
When ...
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How do ping packets get to the ping utility in a NATed network? [duplicate]
I did this test from two PCs at home that are connected to a typical SOHO router, so the router is doing Network Address Translation.
I pinged successfully an IP address from the two computers:
ping 8....
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Shadowsocks doesn't work.ICMP is working but TCP does not
I installed Shadowsocks on a Google cloud server (Debian 5.10.149-2) and ShadowsocksX-NG on Mac.
But it doesn't change my IP address.
If I chose Global mode, no website couldn't be accessed.
What I ...
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windows built-in ping response strangeness
Have cheep noname "managed" websmart switch, generic china. It have default IP 192.168.1.199 When ping it on LAN with my favorit ping program https://github.com/dexit/fping-windows (using it ...
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ICMP 3 / 3 if a port is unreachable
When I want to connect to a non-opened port of my Linux-PC from my Windows PC my IP-stack runs into a timeout after some seconds. So what's happening here ? Does my Windows PC not evaluate any ICMP ...
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How do you display timeouts when using ping6 on macOS?
When using ping6 (IPv6 version of ping), on macOS, I don't visually see the request timeouts when they occur. The ping responses just pause for each request that times out.
A super observant eye will ...
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Devices on Network Intermittently Unable to Ping Each Other
I'm trying to connect to an NVIDIA Jetson AGX Orin DevKit (Ubuntu 20.04) over my local network. I believe that I've set up the SSH server correctly because sometimes I'm able to connect to it. However,...
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Are infinite icmp requests to a server a good way to monitor connectivity?
I have a self-hosted vps server, and I want to always see its status in the system tray of my home machine(if it is reachable or not). For that purpose I wrote a simple bash script that looks like ...
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How to stop the sending of ICMP timestamps replies and requests?
Woo, progress! Updated below! I've been all over the internet looking for an answer to this one. I am using a Raspberry Pi running Raspbian Debian 11. The problem seems rather simple, just blocking ...
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Why I am getting huge different results between ping and mtr?
I have some issues to get stable ping response from any public IPs with Linux/Mac
Under Windows OS, the ping response is stable +/- 1ms roughly; however under Linux/Mac, the ping response could have a ...
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Correct flag to use instead of --icmp-type?
I am trying to set up iptables v1.8.7 on a Debian 11 Raspberry Pi to block ICMP timestamp requests and replies. The tutorial I am following and all the other forums I have looked at say to use the ...
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how to test ntp servers as real servers that responding without using ping test
we have bash script that configured the chrony.conf
script check if ping is ok on ntp1 and ntp2 ( ntp servers )
and then script insert the ntp servers to /etc/chrony.conf ( only if ping success )
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How is ARP reply generated from Windows 10? Sending ARP req from embedded device through ethernet port to windows10 on laptop
I want to send an ARP request using my embedded device through the ethernet cable to my laptop that has windows 10 on it.
I want to receive an ARP reply from windows back to my embedded device through ...
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Detect ICMP requests on a Windows 10 System
I'm looking for a way to detect ICMP requests (e.g. ping) on a Windows 10 System. Unfortunately it does not work with netstat, since ICMP doesn't depend on a port hence all other light weight tools ...
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DHCP Discover : why don't other hosts reply with ICMP 'port unreachable'
When a host sends a DHCP Discover (port 67, UDP), why don't all the hosts (except the DHCP server) reply with an ICMP 'port unreachable' message. This would cause a huge amount of useless data going ...
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Spectrum Router not allowing ICMP Echo Requests
I am currently trying to set up a server off of my Windows 10 PC, after lots of troubleshooting I have concluded that my router is blocking ICMP Echo requests (AKA Ping) from reaching my computer. ...
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Does ICMP use any processes from above layer 3?
I'm doing a project and have to describe the process of a ping from layer 7 to 1. Ping uses ICMP which is layer 3, so the data sits at under a layer 3 header. Does this mean any layers above that just ...
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Why are packets taking 64 hops to connect from my laptop to my laptop?
So, I'm pinging my laptop (from my laptop) expecting the TLL in the reports to be 128 (Because I'm on Windows 10), but I get this instead:
Pinging [REDACTED] with 32 bytes of data:
Reply from [...
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Do Linux (4.15.0-130) and Windows (10) treat ICMP differently?
While attempting to troubleshoot a Windows 10 machine with erratic network problems, I did a traceroute to a host and got somewhat different results from what I see on my Ubuntu 18.04 system with ...
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Traceroute/tracert fails to receive hops return information
I noticed that with some routers/gateways
when I issue a traceroute or a tracert in a 'inner' computer
the hops always fail with:
request timed out
can anybody clarify this?
what information goes ...
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Windows ping to Any IP including 127.0.0.1 hangs, but internet works
I have weird behavior on my Windows 10 operating system. Any ping/tracert command hangs and nothing happens. I have never seen something like this before, and all i have found in the google aren't my ...
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ICMP DUP! packets (but only sometimes)
I have LibreNMS monitoring devices on my home network and it is logging duplicate ICMP packets on my network.
Of the 30+ nodes being monitored, a few (3-4) exhibit this behavior. I can reproduce it ...
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ICMPv6 not reachable under Windows 10 while under Linux it is fine, why, how to fix?
I have just upgraded my ISP and it is finally IPv6-capable. Last year I had an ISP not capable, so... The only thing which does not seem to work under Windows only, is ICMPv6. Since it's an online ...
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Why does the ping programs print so slowly?
I have a raspberry pi as my gateway at 10.0.0.2 with some custom iptables rules for transparent proxy. My Netgear router is 10.0.0.1 with DHCP disabled.
Internet access like browsing the web works ...
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Traceroute: destination IP-address returned for all but first hop. (Debian 9.11)
At some point in the past year, Traceroute behavior changed. Was working correctly prior.
(Debian v9.11 Traceroute 1:2.1.0-2)
Now, first traceroute result, my gateway, is correct, but all the ...
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Why does Node.js's ICMP listen get two responses when I ping localhost?
I am currently using the ICMP NPM package for developing a custom contribution node for node-red.
After a couple of days' testing and making sure everything is okay before publishing I stumbled upon ...
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Get the Destination address from the ICMP header of a ping response
I want to perform a ping request or other fake request and print the whole response from the command line. Practically I'd like to see the same information I can see with Wireshark so that I can ...
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Can't ping anything on local network - general failure
When trying to ping another device within the local network (in same domain) it gives: General Failure. Sent = 4, Received = 0, Lost = 4 (100% loss). Huawei Matebook X Pro with latest version of ...
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Why can't I ping a computer in same network?
I have two computers on the same Wifi router. I want to ping the other one, it does not happen, I get a "destination host unreachable".
Things I've already tried:
I disabled the Firewall on both ...
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Does Windows Firewall block ICMP Timestamp Request (Type 13) by default?
This question is specifically related to the ICMPv4 Timestamp Request (Type 13) message.
When I have Windows Firewall disabled I can send a Timestamp Request from the host and the client will receive ...
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Is really NMAP uses ping packets to consider Host discovery?
I run this command nmap -sn 192.168.0.2 for only Host discovery. And then I started wireshark to see what will going to happen.
I thought It would send ICMP echo req, but the results was very ...
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No internet connection in cmd and msys2 when using USB Tethering and Wifi Hotspot on PdaNet+
I used my phone to connect laptop to the internet using PdaNet+.
There are two options in PdaNet+ which are USB Tether and WiFi Direct Hotspot.
I faced this problem for both the options.
I can ...
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iptables - redirects to local network causes connectivity issues
I have 2 Debian routers and network set up like this:
|
|
| Internet/Public IP
|
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ROUTER A
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|
| 10.97.0.1/16
|
| 10.97.64.1/16 ...
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Allow VRRP on firewall
Deploying an HA redundant solution we use Keepalived with VRRP traffic and a virtual IP. So far I enabled VRRP traffic with the following command (working):
sudo firewall-cmd --zone=dmz --add-rich-...
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Win10 allow incoming ICMPv6 - firewall is behaving weirdly
I finally got it working but I'm a bit confused still.
Has anyone an idea why this approach (netsh) doesn't work on win10?
technet forum
netsh advfirewall firewall add rule name="ICMP Allow incoming ...
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IPv6 ping only possible when target machine pings back
I have a typical "a can ping b but b cannot ping a" problem. I use IPv6 for the ping. What is special in my case is that "b" can ping "a" immediately after "b" pings "a". After some trials, I realised ...
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Network Emulator Toolkit (NEWT) ICMP failing Windows 10
I am trying to use Microsoft's Network Emulator Toolkit to simulate poor network conditions, but it is failing to allow ICMP packets to pass through on Windows 10.
I have tried disabling the firewall,...
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Why does the 2nd ARP request wait until the pings are over to show up?
This problem was presented to me by one of my professors because it only happened after switching from 100Mb cards to Gigabit NICs. The second arp request that comes from the computer being pinged (to ...
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Ping from VMware guest machine to the Ethernet interface of the Host machine
I want to ping from a VMware player guest machine to the Ethernet Interface of the host machine.
The VMware guest machine has an adress in the VMWare Virtual Network:192.168.221.4 so I am able to ...
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Only allow pinging in one direction
How do I allow a ping from the first PC to a second one but block a ping from the second PC to the first one?
I created this firewall rule on both Mikrotik routers:
add action=accept chain=forward ...
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How can Ping not use a transport protocol?
I just learned that Ping uses ICMP directly, i.e. it bypasses the transport layer. How is that possible? Shouldn't an application (L5) use UDP or TCP in the transport layer (L4)? The way I know it is ...
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Spoofed Tunnel Route
What does it mean when tracert always shows a single long jump?
The route below is always the same except the last hop goes
directly to any destination IP address that I choose.
And, how does the ...
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Required ICMP types for IPSec tunnel?
I have IPSec tunnel set up between 2 routers. It used to work fine, however recently I hardened policy in IDS and I started getting alerts about ICMP type 11 code 1 being sent from one router to ...
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Why is 32bytes the default ping size? Is it okay to use less?
I have a very large number of addresses I need to ping on a company network. I want to be as unobtrusive as possible. Would using ping 1.1.1.1 -l 1 reduce the strain on the network? Is the difference ...
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TCP application setting Don't Fragment (DF) Bit
I noticed that some TCP application is setting the DF (Don't Fragment) bit. My research seems to indicate that TCP wants to avoid fragmentation and instead want to adjust the segment size (MSS).
...
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Forwarding ICMP over a server without redirects
I need to test network characteristics like RTT in a network for example by using ICMP pings.
This question is special since I want to force every packet over a server who needs to work like a router ...
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