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48

It's to ensure that the path taken can handle the large packet, not all routes have the same MTU throughout. Having a good MTU will also prevent IP fragmentation.


46

The only benefit of using a big load on a ping is to test the stability of the line. If a line fluctuates or goes offline with a high load, but not with a small load, a standard ping with just 32 bytes won't detect the problem.


21

Is there any relation between ICMP with TCP Not directly. ICMP is IP protocol 1, TCP is IP protocol 6. Other common IP protocols are 17 (udp) and 47 (gre). In other can we guaranty their arrival in the network Typically ICMP is not sent within any type of framework that uses acknowledgements and timeouts like TCP does. So the answer here is no. I ...


18

ICMP consists of a large collection of commands. Disallowing all of those will break your network in strange ways. ICMP allows things like "traceroute" and "ping" (ICMP echo request) to work. Thus that part is quite useful for normal diagnostics. It also is used for feedback when you run a DNS server (port unreachable) which, in a modern DNS server, may ...


17

No one mentioned the PING OF DEATH?? A ping of death is a type of attack on a computer that involves sending a malformed or otherwise malicious ping to a computer. A correctly formed ping message is typically 56 bytes in size, or 84 bytes when the Internet Protocol [IP] header is considered. Historically, many computer systems could not properly handle ...


14

ICMP is a control protocol, meaning that it designed to not carry application data, but rather information about the status of the network itself. The best known example of ICMP in practice is the ping utility, that uses ICMP to probe remote hosts for responsiveness and overall round-trip time of the probe messages. Both Transmission Control Protocol (TCP) ...


10

None of them – they're sent directly over IP. ICMP packets are mainly used for network control, i. e. between routers or ping and many other uses.


8

I use Nping, which is packaged with Nmap. It queries a port of your choosing, for example port 80, and if the port is open, it will receive a response. For example: nping --tcp microsoft.com


7

108.162.198.181 as compared to 108.162.198.81 ^^^


6

How is ICMP unique? I tried to find out whether it is being used in a TCP packet or a UDP packet when running ping, but I kept reading that it's a "unique" protocol and couldn't find a definite answer for this. It is not being used in either a TCP or UDP datagram. Instead look at it like this: IP is an envelope. Transmissions happens when someone hands me ...


6

Ethernet has a minimum frame size of 64 bytes. If you try to send less than that, your system will pad it to 64 bytes anyway, if it's being sent on Ethernet. Ping already sends close to minimum-sized frames: 14 bytes of Ethernet header 4 bytes of Ethernet checksum 20 bytes of IPv4 header 8 bytes of ICMP header = 46 of 64 bytes, so using an 18 byte payload ...


5

MTU stands for maximum transmission unit, ie. the IP datagram size limit (in bytes). Default and maximum MTU allowed by Ethernet is 1500. Let's imagine we have a network like the one below. C is a client; S is a server; X and Y are routers. ___ ___ ___ ___ | C | | X | | Y | | S | |___|========|___|--------|...


5

Just to offer another (unlikely) possibility - I don't have any context as to who is generating the log, and I don't know how often you are seeing these pings, but because you can put whatever you want into the ICMP/ping packets, they are occasionally used a covert communication channel, i.e. an ICMP/ping tunnel. Presumably you'd see frequent large-sized ...


5

This is a normal behavior for an IPv6 router to advertise the IPv6 subnet(s). This is part of IPv6 Neighbor Discovery Protocol (NDP), which uses ICMPv6 to allow automatic configuration of IPv6 on hosts joining a new network. If you want to disable this behavior, you must disable it on the router.


4

The short answer is 'no'. The IP feature you are looking for is the Source Route Option. It is used to determine how a packet is routed at the sender instead of in the network. Because of all the problems that using that option can cause (almost?) nobody will accept and/or honour it. Routing policy decisions are made inside an AS (=Autonomous System). If ...


3

As a workaround (or arguably a fix), disable any network offloading settings on the physical NIC on the host. Open Control Panel, System, Device Manager Expand "Network Adapters" Double-click on your physical NIC to bring up properties. Select the "Advanced" tab Disable all properties with "Offload" in the name (varies by network card). NOTE: You may want ...


3

When one says "Ping", they refer to ICMP ping, as that is what the original ping is. ICMP actually works on a lower level than the UDP & TCP transport protocols and does not use ports[1]: ICMP, uses the basic support of IP as if it were a higher level protocol, however, ICMP is actually an integral part of IP, and must be implemented by every IP ...


2

Given trends in electronic device manufacturing ("race to the bottom"), devices like this are known to "wear out" and perform worse over time, especially if placed in hot areas or areas without good ventilation. I'd look into getting another DSL modem from your provider, or purchasing one yourself. You could also try flashing OpenWRT on your router. ...


2

Your main mistake is: assumption that such kind of traffic will be forwarded. This is not that case. This is outgoing, not forwarded traffic for VM perspective. ICMP replies come to eth0 and go up to protocol stack, thus, you can not see them on tun0 device. For futher details you can look here: https://serverfault.com/questions/554477/tap0-not-receiving-...


2

The device after your router - most likely ISP device - is blocking ICMP protocol packets which means traceroute and ping packets. This is the reason for * * * istead of response times There are tools that could potentialy give the same result to you but they do not use ICMP - they use TCP. The example one is tcptraceroute. Check if this satisfy your ...


2

Yes. Suppose your network looks like this: You want to SSH from A to B. You have sshd running on B; it is listening on on tcp://127.0.0.1:22. B$ pwnat -s 0.0.0.0 2022 127.0.0.1:22 pwnat on B is now listening on udp://0.0.0.0:2022 and is configured to allow connections to tcp://127.0.0.1:22. It is also sending periodic ICMP echo requests to 3.3.3.3 (...


2

You can with hping3 for example by sending a SYN Package to the host: hping3 -S -V host If it is a Webserver you know that port 80 would be open and can send SYN packets to that port hping3 -S -V -p 80 host Or scan the host for any open ports to which you could send packets and he will reply.


2

Most games are fairly inaccurate at determining ping from in-game. Many games don't measure ping at all, but rather game traffic latency, i.e. time taken for an actual game action to complete. OS native ping is almost always more accurate. There are exceptions, but since you didn't say what game you were talking about, I can only answer generically.


2

Destination unreachable is generated by the host or its inbound gateway to inform the client that the destination is unreachable for some reason. A Destination Unreachable message may be generated as a result of a TCP, UDP or another ICMP transmission. Unreachable TCP ports notably respond with TCP RST rather than a Destination Unreachable type 3 ...


2

That is not possible - it's not how Zabbix operates. You must have an item per host. What you can do, is template that item. That allows you to configure it once, then apply that configuration to all your hosts. See the official manual on templates.


2

For those who need an answer: On both routers I matched ICMP type 0 (echo reply) to rule: add action=accept chain=forward dst-address=192.168.100.17 protocol=icmp \ src-address=192.168.11.252 On both routers I matched ICMP type 8 (echo request) to rule: add action=accept chain=forward dst-address=192.168.11.252 protocol=icmp \ src-address=192.168....


2

These two addresses are on differing network segments, so messages cannot cross over. You can specify for the virtual machine the Network Adapter as NAT or Bridged so it participates in the same network segment as the host. Otherwise, you will need to use the route command to add a static route from one segment to the other. There are many articles to be ...


2

This appears to be what Bruce Hartpence calls a “Return ARP.” As described in this excerpt from Packet Guide to Core Network Protocols. The conversation shown in Figure 4-12 illustrates another important facet of ARP—only the host originating the conversation (generating the ARP request) will place an entry for the destination host in its local ARP ...


2

For others that ran into the same issue described above. ICMPv6 echo requests are code 128, not 8 as they are in ICMPv4. That needs to be reflected in the rule. netsh advfirewall firewall add rule name="ICMP Allow incoming V6 echo request" protocol="icmpv6:128,any" dir=in action=allow Notice icmpv6:128 instead of icmpv6:8 in OP's command.


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