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Questions tagged [ping]

For questions about Packet INternet Groper [PING].

41
votes
4answers
215k views

PING port number?

Yesterday interviewer ask me what is port number for ping and which protocol ping use TCP/UDP. After interview I search on internet and found different different results someone says ICMP uses Port 7,...
11
votes
2answers
13k views

traceroute many hops with the same ip

I'm a software developer that sometimes has to do some easy network tasks but knows almost nothing about it. I'm having some problems with a vps I rent ( ENJOY VPS: Unmanaged VPS - Medium VPS) and ...
10
votes
4answers
31k views

Interpreting TTL in ping results

I work for a VoIP service provider and I am working an issue with a customer who has a cable internet connection that's throwing me for a loop. He has a single block, which we'll pretend is 70.141.15....
10
votes
2answers
2k views

Why can't I ping from one computer to another using L3 cisco 3550 switch?

I have configured my 3550 L3 switch to redirect HTTP traffic to a significant Machine: This is my scenario ( PCs instead of Routers): This is the switch configuration: CAT3550# show running-config ...
9
votes
2answers
2k views

Where is Ping's “round-trip time” stored in the IP header?

If we use ICMP's ping, we know the TTL and round-trip time are stored in the IP header. In the below IP header map we know TTL's location, but where is the round-trip time? Is it stored in Options?
6
votes
1answer
824 views

Why can I ping IP addresses from 127.0.0.1 to 127.255.255.254?

I thought that the loopback IP address of my machine is 127.0.0.1. I do not understand why am I able to ping IP addresses until 127.255.255.254.
5
votes
2answers
4k views

What would happen to Ping if two PCs have same IP address with same Subnet Mask on same network?

If there are two PCs with same IP address on a LAN, what would happen if I ping that IP address from another PC on the same network and why?
5
votes
5answers
1k views

Why can't two hosts (in two different logical networks) connected to each other through cross-over cable communicate?

Let us say, i have two computers (hosts) A and B. Where A has been assigned an IP address of 192.168.1.10/24 and host B has been assigned an IP address of 192.168.2.11/24. And both of them has been ...
5
votes
2answers
7k views

How to trace outgoing interfaces?

The Unix command traceroute traces the IP addresses of the nodes from a source node to a destination node. Every node in between has an incoming and an outgoing interface. Executing traceroute -n dst ...
5
votes
1answer
340 views

which host will reply to the ping?

suppose having a LAN which contains : FTP server (10.0.0.1) HTTP server (10.0.0.2) SSH server (10.0.0.3) the LAN use NAT overloading and it has a single public IP (1.2.3.4), now if I ping on 1.2.3.4 ...
5
votes
1answer
601 views

Cisco Router Setup 1841

I need some help. I am new to using Cisco routers (as far as setting them up my self), so forgive me if this is something simple that I am over looking or not understanding. I have a cable internet ...
5
votes
1answer
390 views

Pinging across different subnets? This shouldn't work but it does

I have two computers: PC1 and PC2. PC1 has an IP address of 10.0.0.1/30, and PC2 has an IP address of 10.0.0.6/30. They are connected directly to each other with a crossover cable. My understanding is ...
5
votes
1answer
179 views

How are ping times computed

I have been graphing ping (IPV4) responses times/vs packet size. I was expecting to see a discontinuity of around 2*MTU/BandWidth in response time around the MTU boundary (actually, around 1464 byte, ...
4
votes
3answers
651 views

Understanding hubs and switches

Newbie here. I'm trying to understand how hubs and switches work. I read that hubs only forwards to all ports but a switch only forwards to the port it needs to. So, If I connect 3 computers to the ...
4
votes
2answers
432 views

does the DSL distance really add more latency

I've been using dsl internet for quite a while and having a ping from Algeria to France of about 90 ms , after trying to ping some locations in Algeria , i am getting about 50 ms, ping to my gateway ...
4
votes
4answers
2k views

ARP table does not store devices responding to a broadcasted ping request

I have got a simple question, I am doing a broadcasted ping request on my local network, using a Mac with the latest Yosemite 10.10.4. So I ping 255.255.255.255, I get responses from a bunch of ...
4
votes
3answers
556 views

Why I cant Ping An Address across my a routed link

I have two layer 3 switches (Main And back up) and a palo alto firewall main switch connects to the firewall with a routed link port(gi1/1 ip add 10.1.70.2)- firewall (10.1.70.1). All connectivity is ...
4
votes
1answer
191 views

Strange ping over frame-relay network

Buffing up on Frame-Relay for testing EIGRP nuances over FR for CCNP - topology and relevant show command output here: http://imgur.com/a/Ch6Sh#0 Relevant PVC is between DLCI 103/301 (R1/R4) Why ...
4
votes
2answers
336 views

Why R1 is not reachable to R3?

I didn't configure any routing protocol to any of the router and tried to apply static routes in order to get out of the network and I've configured static routing in a manner that if R1 sends a ping ...
4
votes
1answer
5k views

Why we can not ping to multicast address 224.0.0.9 of RIP

We know that RIP v2 uses multicast address 224.0.0.9 for periodic broadcast of routing table. So it means that every router configured with RIP V2 is monitoring for any packet with destination address ...
4
votes
1answer
3k views

Cisco 3725 - ping encapsulation failed

I am unable to ping from R1 to R2. debug ip packet detail returns IP: s=172.16.12.1 (local), d=172.16.12.2 (FastEthernet0/0.12), len 100, encapsulation failed. I understand this means it can't resolve ...
4
votes
1answer
238 views

Latency in P2P Circuit

I have one P2P Circuit from our HQ to a secondary office. the distance between them is approx 2kms. Earlier when the Circuit was delivered at that time we were having an RTT of 3-4ms. It is a 10Mbps ...
3
votes
4answers
5k views

When a ping is lost, what happens?

Suppose that the message you are sending does not reach the destination, such as a ping. Is the content of that message protected? How is a retransmission accomplished?
3
votes
3answers
18k views

Ping a private IP address in another network

We all know that PCs on a LAN use private IP addresses such as 192.168.2.3, etc. Now my question is, how can a PC say mine having a private address of 192.168.2.3 communicate with other LAN PC ...
3
votes
2answers
1k views

Strange router's MAC address from ICMP Echo Reply?

Using Wireshark to capture ICMP packets (Windows) using ping to google.com, I can see the source-MACAddr of the ICMP Echo replies is not the same as the MAC address of my direct router (which is the ...
3
votes
1answer
12k views

What is first? ARP vs ICMP

I want to know what is first after STP. There are just three devices, switch and two hosts. A switch is not configurated and two hosts have each IP by static. Of course, two hosts are connected to ...
3
votes
4answers
17k views

Cant ping across router?

I am trying to set up communication across a network, and I have run into a bit of a problem. In the diagram below, why is it that I cannot ping host 2 from host 1? Router 1 has interfaces on both ...
3
votes
2answers
1k views

Cannot ping subinterfaces on Cisco ASA 5508

I am not able to ping the inside subinterface on my ASA 5508-x. When setup this way, I am able to ping the interface: interface GigabitEthernet1/3 nameif inside security-level 100 ip address X.X....
3
votes
1answer
89 views

Can't ping the management IP of Switch

My topology is: I am logged in to R1. I can ping 10.0.0.2 on R2 and 198.51.100.1 on R2, but can't ping the management IP of sw3 (198.51.100.2). What am I doing wrong? R1#sh ip arp Protocol Address ...
3
votes
2answers
61 views

are the RTTs additive?

By using the ping, I calculate the RTT between A and B. I calculate the RTT between A and C. I calculate the RTT between C and B. Is it possible to compare the RTT of topological link A->B with the ...
3
votes
1answer
23k views

linux ping mtu and fragmentation

I've been experimenting with the ping utility on Linux. I set a mtu of 500 bytes on my router. Now, when I ping to an external host, I get the following output: ping -c 3 -s 1300 10.0.2.1 ...
3
votes
4answers
4k views

Are ping-times directly related to location/distance?

Suppose I want to determine if an IP is located in my country, without a third-party servvice. Could I estimate that to a certain degree by measuring ping times? Or is it better to look at the number ...
3
votes
1answer
79 views

Same hop appears 4 times on a traceroute [closed]

When I traceroute bbc.co.uk in my home Network the first hop appears 4 times. What could be causing this ? @Latitude-7480 ~ $ tracepath bbc.co.uk 1?: [LOCALHOST] ...
3
votes
3answers
1k views

CRC errors and ICMP packets loss correlation

I would have a question regarding physical problem detection in a link with ping. The assumption is as follows: I have a fiber or cable with much of noise due to bad hardware (bad cable or bad ...
3
votes
2answers
4k views

Ethernet padding

I'm using Wireshark for my project. I sent a ping over to Google.com and Wireshark said that the length was 57 bytes(when I received the reply it was 60 bytes long and it contained 6 bits of padding. ...
3
votes
1answer
469 views

Ping unlocks ipsec vpn

I have a ipsec vpn with a foreign company, this connects my network with their network and they have a different ip subnet. Ipsec is made by a pfsense gateway/firewall. I'm sure it is well configured,...
3
votes
3answers
449 views

Cannot access certain web page. Ping succeded traceroute didn't

This is my first question on forums at all. I work as a network support engineer and I have a little issue at work and I would really appreciate advice from you. Cannot access the url www.reach2.org ...
3
votes
2answers
3k views

Computer unable to ping another over two routers

I am using Cisco Packet Tracer to simulate a network of two routers each connected to a switch and two hosts per switch. The network is setup as so: I'm using a default subnet mask of 255.255.255.0. ...
3
votes
2answers
733 views

OSPF can't ping other network segments

I'm trying to setup a very simple OSPF network with Vyatta. From the best of my knowledge they let all traffic in by default, and I haven't set any firewall rules. The vyatta instances are launched as ...
3
votes
2answers
608 views

ping, traceroute not working [closed]

I was going through a Networking course online and they instructed me to try ping and traceroute commands on Linux for network checking. I have Fedora OS v22 and am using WLAN Dlink Router for ...
3
votes
1answer
4k views

Cisco Switch Can't Ping Attached Device

PC1-VLAN1======Switch : Successful pings from the switch PC1-VLAN2======Switch : *Unsuccessful* pings from the switch I've got a single switch with a static IP directly connected to PC1 with a static ...
3
votes
2answers
801 views

Disable ping replies on brocade switch

What is the command to use to disable ping replies from a brocade switch? Baasically, I am trying to disable any outbound ping messages to inbound ICMP request messages. I stumbled upon brocade-...
3
votes
2answers
790 views

POST duration over https vs ping time? [closed]

I'm trying to get a first-order evaluation of how network latency / Round Trip Time (RTT) T, as characterized by ping time, will affect the duration of consecutive sequential POST requests over an ...
2
votes
2answers
3k views

Weird ping back from Cisco Router

I just got this router, fresh out of the box. I turn it on and set it up and I get these weird IPs: Pinging 192.168.1.1 with 32 bytes of data: Reply from 74.x.x.254: TTL expired in transit. Reply ...
2
votes
2answers
85 views

Public IP addresses

Are all Public addresses connected to each other? Can I ping my friend's public IP address on another side of the world? or public addresses are divided into groups( something like private and public ?...
2
votes
3answers
195 views

Ping command through network

I have been trying to understand how and what tables are populated ( if they are clean at the start) when a ping command goes through. Lets say I have this network: I want to send a ping command from ...
2
votes
3answers
71 views

Pinging computer on a local wireless network, what exactly happens?

I'm trying to get a better understanding of networking in general. Here's one of the many questions I got: What exactly happens (network wise) when I ping 192.168.0.5 from 192.168.0.3, when both are ...
2
votes
3answers
2k views

When is 'Timestamp' and 'Timestamp Reply' are used in ICMP protocol?

I started the packet capture in my laptop through Wireshark application. Now through cmd, I pinged some server (say, www.google.com). And i stopped packet capture and analysed the packets being ...
2
votes
3answers
743 views

Switches Can't Ping Each Other but PCs Can

I have an HP ProCurve 2910al running pretty much factory defaults on it at 192.168.1.50. There are 2 VLANS on it. Ports 1-12 are VLAN 1 (untagged) Ports 13-21 are VLAN 2 (Untagged) Port 22 is a ...
2
votes
2answers
31k views

Difference between ping timed out and destination host unreachable

I'm pinging from a Windows Box to a device that I rebooted. PS C:\Users\administrador> ping 192.168.2.10 Pinging 192.168.2.10 with 32 bytes of data: Control-C PS C:\Users\administrador> ping -...