Questions tagged [icmp]

ICMP is the Internet Control Message Protocol. It is used for diagnostic purposes, for querying information, and for transmitting network-level error messages. ICMPv6, the version for IPv6, is also used for configuring nodes on the link.

Filter by
Sorted by
Tagged with
0
votes
0answers
25 views

Workflow for compiling and installing a single existing kernel module?

I am working on creating a patch in the Linux kernel. All of my work occurs in the file net/ipv4/icmp.c (and associated header.) So far, every time I want to test my code, I run make -j $(getconf ...
12
votes
4answers
777 views

Is there any utility for performing ICMP testing (“ping”) in only one direction?

I've been having trouble with some network configuration lately which has been tricky to resolve. It seems this would be much easier to diagnose if I knew which direction the traffic was failing to ...
1
vote
1answer
17 views

Allow/Deny ICMP “on demand” from normal user (Sysctl, Sudo, /proc)

I would like to set up an account on a CentOS 7.8 that can allow/deny ping (icmp echo) "on demand". This works great logged as root, example : echo 0 > /proc/sys/net/ipv4/...
0
votes
1answer
39 views

Respond and send ICMP only to certain user's mac address

I need to block ICMP requests for all user's except the groupt that is supposed to manage the VM. Since we access the VM via VPN we have a different IP every time we send a ping to the VM, can I only ...
0
votes
1answer
140 views

What is the filter expression to only sniff ICMP packets?

What is the filter expression to only sniff ICMP packets given the source IP address is 18.23.54.78 and the destination IP address is 12.67.24.89? The filter order must start with the protocol name ...
0
votes
0answers
31 views

Smokeping/Cacti ping probes when ICMP is disabled

I have installed smokeping and I want to use it to draw an RTT graph to a couple of servers. The problem is that some of those servers have their ICMP disabled. I have found another ping tool which is ...
0
votes
0answers
30 views

Will Linux kernel verifies if source MAC and IP are match in ICMP request?

I have following configuration of the systems: When I issued ping 192.168.1.200 form Switch, I found the ICMP request packet's source IP in IP header is 1.1.1.2 but the source MAC in L2 header is ...
0
votes
1answer
44 views

Strange ICMP packet

I have an Ubuntu server with iptables that only allows echo request and reply for ICMP and log and drop other ICMP traffic. There is an always on SSH connection between this server and another Ubuntu ...
1
vote
2answers
143 views

Server does not respond to ping - ICMP is received and nothing happens

I have a server with 2 interfaces connected with dhcp to two different subnets. These 2 different subnets are connected to the same switch into 2 different interfaces. # ip a 1: lo: <LOOPBACK,UP,...
0
votes
0answers
682 views

iptables: how to block traceroute and allow ping?

Hi first sorry for my english. I'm trying to block traceroute --icmp (tracert) while still permitting the ping, using iptables. The problem is that when I permit the traffic of echo request, to allow ...
0
votes
0answers
22 views

Pinging default gateway on a Linux virtual machine

I have two question about the network. I started to ping my router from my Linux virtual machine and I have intercepted these ICMP frames. I noticed that the destination MAC address is not my router ...
0
votes
1answer
59 views

View packet data of ping

Is there a flag or other utility (perhaps tcpdump?) that can be used to see the outgoing packets that are sent via the ping utility? For example: $ ping -c 5 google.com PING google.com (172.217.14.78)...
-2
votes
1answer
2k views

How to allow icmp for your machine? [closed]

I want to allow icmp (ping) for my server. I was reading about IPTables and read that to allow a ping to your machine, you need to have INPUT rule as well as a FORWARD rule. Because INPUT only handles ...
1
vote
3answers
91 views

Tcp connection packets ignoring network delays, ping shows delays [closed]

I've introduced a 2000ms latency to all network packets using openwrt netem module. # This is run on the terminal of the OpenWRT router tc qdisc add dev wlan1 root netem delay 2000ms I can clearly ...
3
votes
1answer
104 views

Host unreacheable from laptop but reacheable from desktop

I have a Synology NAS at home (let's call it ananas), it is attached to my router via ethernet. I also have a desktop (let's call it Aero), it is connected to the same router via wifi. I configured in ...
0
votes
0answers
30 views

Iptables rules enabled for allowing icmp/ping for only specific IP address with RHEL7 OS not working [duplicate]

The server where iptables rules are enabled is RHEL 6.4. From this server, I tried to allow icmp echo request from only one specific IP address (host with RHEL7.5 OS). I used the following rules: ...
26
votes
12answers
30k views

How can I ping multiple IP addresses at the same time?

I'm aware of the methods where you can run a Bash for loop and ping multiple servers, is there a Linux CLI tool that I can use which will allow for me to do this without having to resort to writing a ...
1
vote
1answer
464 views

TAP/TUN capturing ICMP packets

I'm trying to capture raw ethernet packets into a user space program. Having read about the TAP/TUN capabilities of the kernel, I went on and created the following setup: Two systems connected ...
1
vote
0answers
133 views

How to view ICMP Redirect Logs

I have read on multiple sources that there is are logs for rejected ICMP redirect messages, one of them being "Understanding Linux Network Internals: Guided Tour to Networking on Linux" By Christian ...
0
votes
1answer
79 views

Should I remove ICMP Protocol from firewall rules base on security concern?

As you can see from the screenshot of GCP firewall rule page, should I remove ICMP Protocol from firewall rules base on security concern? Will it lower the chance of being attacked? I'm using CentOS ...
6
votes
1answer
1k views

How come one can successfully ping 127.0.0.2 on Linux?

On a FreeBSD system with a loopback network interface … % ifconfig lo0 lo0 link up loopback drv_running running multicast nd6 performnud auto_linklocal no_radr link rxcsum ...
1
vote
1answer
2k views

It is possible to traceroute without touching ICMP?

I often run into a situation where I want to traceroute an IP without root or NET_RAW cap in Linux. I have attempted to send a UDP packet with a small TTL but no ttl error is emitted at all. It seems ...
0
votes
1answer
1k views

How to Disable Ping ( TCP ) in Linux all the time? [closed]

I want to disable ping response all the time. I use the following command for disable ICMP ping iptables -A INPUT -p icmp --icmp-type echo-request -j DROP what should I do for disable TCP ping ?
0
votes
1answer
31 views

Exclude interface when send ICMP ping

for build small linux application I need to check the internet connectivity of the system. But my box have multiple network interfaces with interfaced for backup internet connection. I need to do some ...
1
vote
1answer
757 views

How to check whether kernel received MLD query or not?

On the Internet I found this command netstat -p icmp6 -s which can dump how many MLD queries received by the kernel. But I have Busybox for my system and because of this I'm unable to run netstat ...
0
votes
0answers
161 views

mtu 9000 issues only on tcp and not icmp possible?

I have a connection between two datacenters and rsync between them stalls often. I think it is related to the mtu 9000 (I actualy set it to 8900 because of some possible vlan use) I have the ...
40
votes
3answers
10k views

What Linux process is responsible for responding to pings?

I have a Linux based process controller that occasionally locks up to the point where you can't ping it (i.e. I can ping it, then it becomes no longer pingable without any modifications to network ...
0
votes
1answer
73 views

I have disabled all rules in firewall, but still can tracert from LAN

I have disabled all positive rules in firewall on my pfSense box, and I can't browse Web, but I still can tracert 10.10.0.251 from LAN machine and receive 3 hops from my ISP (behind the router). ...
4
votes
3answers
3k views

tcpdump -i any doesn't work on FreeBSD

How to listen all interfaces on FreeBSD with tcpdump > tcpdump -i any tcpdump: any: No such device exists (BIOCSETIF failed: Device not configured) (I would like to listen ICMP)
2
votes
1answer
5k views

UDP port unreachable although process is listening

I am experimenting with communication over UDP port 6666 (the goal is setting up a listener for netconsole, but that's not really relevant here). On the listening side, nc -luv 6666. On the sending ...
13
votes
2answers
32k views

How to Disable Ping Response (ICMP echo) in Linux all the time?

I want to disable ping response all the time on my Ubuntu operating system, the following commands work but only until the system reboots: Ping off: echo "1" > /proc/sys/net/ipv4/...
1
vote
0answers
432 views

Reading MLDv2 queries using an IPv6 socket

I have mrd6 installed on my raspberry pi. It registers with a local interface (tun0) and periodically transmits MLDv2 queries over it. According to [RFC3810], MLDv2 message types are a subset of ...
4
votes
0answers
3k views

No buffer space available - ICMP

I'm trying to set up a Heartbeat client on a linux machine (CentOS Linux release 7.3.1611) which is sending ICMP echo requests to roughly 1300 hosts. However, in future this number will be higher. The ...
1
vote
1answer
2k views

Network Interface VLAN static addressing

I have been trying to configure the static IP addresses with Ubuntu 16.04 Dabian version. The network as follows in the graph I have been failing to ICMP (ping echoing) between the Client and the ...
0
votes
1answer
288 views

What is ICMP reply for all-zero host-bit IPv4 address?

We all know that the first address of any sub-net is network identifier and it can't be assigned to any hosts. For example in network 10.1.1.4/30, the address 10.1.1.4 is network identifier. If ...
4
votes
2answers
12k views

How to DROP icmp requests with firewalld?

How to DROP icmp requests with firewalld? An equivalent example instead using iptables would be: $ iptables -A INPUT --protocol icmp --in-interface enp0s8 -j DROP The above produces the desired ...
0
votes
1answer
2k views

How to configure iptables ICMP rules on a router?

I'm trying to configure iptables rules on a router that allows ICMP (PMTU-D, ping, traceroute, etc.) to function. GOALS: 1) Allow all ICMP outbound traffic initiated from the router and internal ...
2
votes
0answers
806 views

How to make Linux stop sending IPv6 ICMP redirects?

In case of IPv4 we have net.ipv4.conf.all.send_redirects flag, but it's not available for IPv6. Is there anything better than this? ip6tables -A OUTPUT -p icmpv6 --icmpv6-type redirect -j DROP For ...
7
votes
1answer
940 views

MTU (IPv4) tests in Linux

I noticed I have several networks with all ICMP messages blocked at the firewall level, except for ICMP echo and reply. I know that there is a need at least ICMP messages type 3 in IPv4 have to be ...
1
vote
2answers
2k views

How to disable ICMP timestamp on AIX - not using firewall

On AIX 6/7 how can we disable this function? I cannot see any in "man no". Installing firewall just because of this is not really an option.
0
votes
2answers
1k views

Only ping fail output should get visible

Is there a possibility for getting only the error output when running the ping command? Its very tricky to understand if we have n number of server monitoring. icmp_seq will obviously show the drop ...
0
votes
0answers
248 views

iptables REJECT with delay

Simulating an unreachable host: iptables -I OUTPUT -d 192.168.1.42 -j REJECT And then ping 192.168.1.42. It rejects immediately, so the terminal is flooded with Destination Port Unreachable. How to ...
2
votes
1answer
3k views

Forward ICMP Ping Packets to Interface

I've got a script that listens for ICMP ping packets (containing data payload) and while this works if you run it from command line, it doesn't work in a Docker container because ICMP ping packets are ...
2
votes
1answer
3k views

ICMP - Destination unreachable (Port unreachable)

I have two Ethernet-wired connected devices. I gave to both of them address from same sub-network. As result I can see second device in arp-table of the first. $ arp -a ? (128.247.77.90) at 10:60:4b:...
1
vote
0answers
71 views

Can two android devices in different network(3g) comunicate themselves with ssh connection?

I have two rooted android devices with different isp (I use different 3g connection for them) and created a double ssh connection (I can with a public ip server) communicating both to this server (I ...
1
vote
1answer
809 views

iptables REJECT icmp-admin-prohibited

The iptables man page says: Using icmp-admin-prohibited with kernels that do not support it will result in a plain DROP instead of REJECT I have been unsuccessful at finding out at which kernel ...
4
votes
2answers
12k views

How to accept ICMP redirects?

tcpdump showed me there are some ICMP-redirect in my network (KVM virtual-machines, bridged network). I decided to take a closer look on them and how my system behaves and how it looks. I found it ...
0
votes
2answers
628 views

Subnet routing problem

In my LAN I have an openwrt router configured with IP 10.0.0.1. It is the default gateway (and dhcp server) in my LAN 10.0.0.0/24. Now I have a new network, say 10.9.0.0/24 used by virtual machines. ...
4
votes
2answers
38k views

ICMP : Port unreachable error even if port is open

I am testing my Debian Server with some Nmap port Scanning. My Debian is a Virtual Machine running on a bridged connection. Classic port scanning using TCP SYN request works fine and detects port 80 ...
2
votes
2answers
870 views

How to get different types of ICMP

I have a task on which I have spent a lot of time. I am not fluent in Linux, but I can manage basic things. The task is to gather different types of ICMP packets. I can harvest them by tcpdump (which ...