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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What is the purpose of using a large ping packet?
While analyzing some traffic logs, I noticed a node pinging its gateway with a large ping packet size, ranging from 700 bytes to 1 MB. It's a constant ping from node to gateway and the size per ping ...
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what is type of ICMP packets? TCP or UDP
The ping packet is a type of ICMP packet. Is there any relation between ICMP with TCP? In other words, can we guarantee their arrival in the network?
I want to know if ICMP packets in the network are ...
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Linux: How to monitor incoming pings
Can I somehow monitor incoming pings on a Linux machine? netcat doesn't seem to support that.
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What is ICMP broadcast good for?
To configure Linux to ignore ICMP broadcasts (to protect from SMURF attacks), I have added the following line to /etc/sysctl.conf:
net.ipv4.icmp_echo_ignore_broadcasts = 1
Anyone knows what are the ...
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How ping a server which has ICMP blocked
I'm trying to ping a server which has ICMP blocked with normal ping. It's showing:
Request timed out
Is there any other method to ping it?
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What are reasons to disallow ICMP on my server?
An EC2 Instance has ICMP services disabled by default. While it's not totally clear to me why, I think it's because it could be a potential security risk. At the moment I'm enabling Echo Responses ...
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How do I forward traffic between Tun device and eth0?
In summary, I would like to have Tun device traffic forwarded
back and forth through another network interface that has internet
connection. While I can see the traffic going out to internet and ...
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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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Can the maximum ping size of 65500 bytes can be increased?
Can I override the default maximum size - 65535 bytes of ICMP ping packets? If - then How?
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Ping doesn't work when using QEMU user mode networking
I try to use network in guest system. I installed an OS in a virtual machine, but I did not get the network configured. When I try to ping, for instance google.com I get the IP address for the domain, ...
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Why ICMP is different that TCP and UDP? [closed]
what is the difference between Internet Control Messaging Protocol over Transmission Control Protocol and User Datagram Protocol
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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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SSH and PWNAT for SSH Connection Between Two Separate NATs
Is it possible to use pwnat and SSH to establish a "peer-to-peer" SSH connection between two machines that are behind two separate firewalls/NATs?
If this is possible, what are the steps that would ...
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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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Is there a way to test alternate IPv4 routes?
i am using Hurricane Electric's Tunnel Broker service to get IPv6 connectivity.
TunnelBroker lets you have access to the IPv6 Internet by using a standard IPv6 tunneling protocol. You send IPv6 ...
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What could be causing problems on pinging Windows 8 machines?
Here at my job I have five machines with Windows 8 Consumer Preview installed on it. Today I was testing the network conectivity and any of the five machines answered to a ICMP ping request (but ...
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Difference between TCP and IP tunnelling?
Can someone please explain in terms of the OSI (or TCP/IP) layers, what is the difference with what goes on when you tunnel IP or TCP, say over the ICMP protocol (although the latter doesnt really ...
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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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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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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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Linux Virtual machine can't ping Google, while Host can do it
Assumptions:
You have a Windows 7 Ultimate as your host.
You have a Linux Kali 2 as a VMWare Workstation virtual machine on this host.
Your network adapter is bridged on the VMWare(Version 10.0.3).
...
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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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ICMP redirect: how to test it with icmpush
I want to see how the routing table changes on a Linux system, when an ICMP redirect is received.
For that I use
icmpush -v red -sp current-gateway -gw new-gateway -dest google.com -c host -prot tcp ...
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Virtualbox machine cannot ping its own public IP
I have a strange problem. I have a bridged network adapter on my virtualbox machine (Kali Linux) - with assigned IP address with my local LAN pool (192.168.0.22) and I can ping e.g google.com (DNS ...
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udp client sending ICMP “port unreachable” when receiveing messages from the server
(Note: I moved this question from StackOverflow, because it's to be considered off-topic there, better fits here, and still unsolved)
I have a udp client using luasocket, basically doing this (with a ...
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ICMP Fails after first packet
I'm trying to ping any ip, other than my LAN IP & localhost, it fails except the first packet!!
Snapshot from CMD with the pings
But Wireshark capture shows that the ICMP is success!!
Someone ...
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Firewall blocks ICMP even with Allow rules, even when disbled
Sometime early October (right after update Tuesday???). My Window 7 home machine stopped responding to anything incoming. Effectively breaking iTunes, Sonos, TiVo Desktop, RDP etc. But all those ...
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Traceroute to IP address fails, but traceroute to domain name with same IP address is okay. Why?
When I traceroute to this IP (108.162.198.181) it stops after 1 hop. But tracerouting to a domain (www.gomodule.com) with the same IP shows 9 hops ending in that target.
traceroute to www.gomodule....
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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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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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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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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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Why does ICMP Echo Request and Echo Reply packets contain a Data portion?
The ICMP Echo Request and Echo Reply packets contain a Data portion. For example this is an Echo Request packet (that was sent in Windows using the ping command):
As you can see, there is a Data ...
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Is ICMP port unreachable error generated by both TCP and UDP? [closed]
A program on machine X attempts to open a UDP connection to port 5376 on a machine Y, and a TCP connection to port 8632 on machine Z. However, there are no applications listening at the corresponding ...
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traceroute on Linux displays '* * *'
What is going on? If I run traceroute google.com it outputs 192.168.0.1 for the first router (which is correct) and threee *'s for the rest. I have tried disabling the FireWall on the router (192.168....
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Unable to send ping from host A via B to C
There is a network of three computer.
Problem: Host A (192.168.1.1) can send ping to host B (10.10.0.5, also 192.168.1.2), but can not to send C (10.10.0.6, 10.10.0.7).
Host A say: "10.10.0.6 = ...
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Disable ping on Windows (not block)
How can I disable Windows ping from replying?
Is there a service I can kill?
I don't want to block it via a firewall, as I can my own ping service running (custom application).
tia.
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Cannot ping or ssh from lan to virtual machine
I have next setup:
My home lan = 192.168.1.0/24
My virtual lan = 192.168.207.0/24
My laptop = 192.168.1.109 (dhcp OS=Windows7)
My desktop = 192.168.1.206 (fixed ip OS=Windows8)
My virtual machine ...
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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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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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Exact meaning of ICMP protocol 1 port xxx unreachable in a ping exchange
A tcpdump of a ping session shows the following two lines:
IP gateway.comp.com > somehost.comp.com: ICMP redirect 10.8.0.10 to host othergateway.comp.com, length 68
IP gateway.comp.com > ...
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Varying TTL on LAN
I've got a wireless router behind a router-modem.
If I ping my router-modem (TWO hops), all seems well :
robut@host:~$ ping 172.X.X.36
PING 172.X.X.36 (172.X.X.36) 56(84) bytes of data.
64 bytes ...
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Why am I having trouble using ptunnel to connect to machine in DMZ from WAN?
I'm trying to have a play with ptunnel, I have it running (listening) on my raspberry pi in my DMZ and I can connect to it from my LAN and tunnel ssh over it, but I can't get it to work over my LAN.
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How is ICMP unique?
I just read this in Wikipedia:
Although ICMP messages are contained within standard IP datagrams,
ICMP messages are usually processed as a special case, distinguished
from normal IP processing, ...
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Can a home PPPoE connection access all websites, regardless of the site infrastructure's MTU settings?
I'm just trying to get my head round MTU, MRU and MSS.
My interest initially came from the answer in this post: Security risk of PING?:
Some ICMP packet types MUST NOT be blocked, in particular ...
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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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Can I ping a host that has disabled the ICMP Ping option?
I need to know if it's possible to compare and test how fast is an IP (ie: any web or game server) relative to my location (in terms of network latency), even if they have disabled ICMP/Ping requests ...
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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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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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Block ICMP flood from a specific IP with pf
I'm getting a lot of ICMP throttle messages in my system.log:
Apr 11 20:45:28 kernel[0]: Limiting icmp unreach response from 1054 to 250 packets per second
Apr 11 20:45:29 kernel[0]: Limiting icmp ...
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