Questions tagged [icmp]
For questions about the Internet Control Message protocol.
135
questions
3
votes
2
answers
1k
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 ...
- 183
7
votes
2
answers
6k
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?
- 177
2
votes
4
answers
288
views
Allow necessary protocols to ping when configure firewall
I am configuring a firewall hardware, which is connected between my laptop and lab LAN (lab LAN is also connected to other computers as well as Internet). My objective is to allow the ping between my ...
- 271
3
votes
1
answer
723
views
ICMP packet with correct mac address but wrong ip address
I was wondering what would happen if you send an ICMP request with the correct mac address but the wrong ip on a local network. Would the request reach the computer with the correct mac address since ...
- 31
1
vote
1
answer
462
views
How can I test my ping application for proper detection of ICMP return types and codes [closed]
I have developed an application that partially replicates the functionality of the builtin ping application, essentially sending an ICMP packet, receiving the response, and parsing the header.
...
- 258
1
vote
1
answer
504
views
Different types of ICMP [closed]
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 ...
- 11
0
votes
1
answer
1k
views
ASA and ICMP - can't see drops via aspdrop - why are drops happening?
Pinging from one SRC to a few DST's I can see some drops happening on my captures for some attempts and none for others. Wondering how I can see what's really happening to ALL of the arriving icmp ...
- 3,310
5
votes
2
answers
5k
views
Calculating checksum for ICMPv6
Referring http://www.faqs.org/rfcs/rfc1071.html, I try to deduce the c code for calculating the checksum for ICMPv6. But check with the checksum parse by wireshark, I find that the answer got from my ...
- 373
3
votes
1
answer
2k
views
ICMP Redirects uncovers routing issues
So our newly configured servers have uncovered some switch configuration issues.
In /etc/sysctl.conf we have the following:
net.ipv4.conf.all.send_redirects = 0 # CIS 4.1.2
net....
2
votes
1
answer
3k
views
Ping domain name using sourced interface
Problem: I want to be able to ping a domain name, sourcing from a particular interface on a Cisco router.
Scenario: I have Router-A, an it has a management address of 1.1.1.1. I can only connect to ...
- 480
4
votes
1
answer
18k
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 ...
- 41
2
votes
6
answers
115k
views
How Can I use "ping command" with source?
I can not use ping 'target' source 'interface'
ping 192.168.0.2 source lo0
% Invalid input detected at '^' marker.
It's possible if I use "ping"
R2#ping
Protocol [ip]: ip
Target IP address: 192....
3
votes
1
answer
445
views
ICMP response to source IP when the payload of IP packet is not ICMP?
Let us say I create a valid packet (contains telnet request) with TTL value less than the TTL value required to reach the destination IP. Will the computer that receive the IP packet with TTL=1 (...
- 927
2
votes
2
answers
201
views
Traceroute probes
In traceroute, when a * is recieved, it could mean the router didn't reply due to various reasons- either the router is busy processing other packets or ICMP is blocked. I think few ISPs configure ...
0
votes
2
answers
3k
views
I can ping but ports are closed
I am using nmap to scan open ports of a device (Android smartphone), and nmap returns me that all 1000 scanned ports are closed. Right.
But in the same time I can ping the device. I thought that ...
- 713
8
votes
6
answers
89k
views
Pinging broadcast address [closed]
I am using Linux. I read somewhere on the internet that pinging the address 255.255.255.255 will ping everyone in the network segment. And it will return every IP addresses in that subnet. But when I ...
- 545
1
vote
1
answer
646
views
traceroute through Twice NAT'ing
interesting traceroute I am getting thru a firewall where we are NAT'ing both Source and Destination. I am wondering if it is possible to get this to work. We are trying to set up a traceroute monitor ...
- 813
2
votes
1
answer
1k
views
ICMP "echo request" handling on routers running Cisco IOS-XR
I am aware that ICMP "echo request" messages addressed to router are handled in process switching in case or routers running IOS. However, what about Cisco ASR9K routers running IOS-XR? Is the ...
- 1,177
8
votes
2
answers
10k
views
What are the SNMP MIBs for Cisco IPSLA ICMP echo
I have two ipsla operations set up:
ipsla
operation 10
type icmp echo
source address 10.0.0.1
destination address 10.0.2
frequency 30
operation 11
type udp jitter
tos 128
source ...
- 211
1
vote
1
answer
1k
views
ICMP Redirect , static routing
I am learning about ICMP Redirect and I struggle with understanding it.
For example, I have a network like this :
I want to communicate from PC0 to PC1 which are on different subnet and at the ...
- 13
6
votes
2
answers
101k
views
dont fragment bit PING TOOL
Actually my machine wwan0 MTU is 1500
ashokkrishna@ashokkrishna-Lenovo-B560:~$ ping -s 1490 example.com
PING example.com (93.184.216.119) 1490(1518) bytes of data.
1498 bytes from 93.184.216.119: ...
- 545
3
votes
2
answers
860
views
Cisco 2600 IOS ICMP packets viewing
Does anyone know how to view ICMP packets (ping), if possible, traversing through a Cisco 2600 router, that is, how to use the console connection to the router (the usual for configuration) to display ...
- 147
3
votes
1
answer
1k
views
What Does ICMP Code 9 Mean For a Type 8 Packet?
I am currently doing an assignment that requires us to generate ICMP packet with various types and codes. I have consulted the RFCs as well as various other place. Many of the types and codes I get ...
- 43
11
votes
2
answers
53k
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....
- 305
19
votes
2
answers
31k
views
Traceroute - every packet has TTL == 1
I'm working on Wireshark lab-IP in Computer networking - A top down approach and I don't understand why every packet that normally expired has a TTL of 1.
Here is my Wireshark capture file.
https://...
- 193
0
votes
1
answer
381
views
Ping reply is slow after applying inbound ACL
I applied inbound ACL to block ping request from host IP to host IP. The effect after that is ping reply from unblocked IP on the interface that has been applied the inbound ACL is slow/loss.
Any ...
- 89
6
votes
2
answers
1k
views
IP Traceroute RFC 1393
Is RFC 1393 implemented by real routers in practice?
Are there any tools that generate traceroutes using it?
- 163
6
votes
2
answers
9k
views
USE of ICMP echo request in DHCP
In RFC2131 (page 12) it's been mentioned that
The server should use whatever information is available in the
configuration information repository to choose an address to reuse.
For example, ...
- 449
18
votes
1
answer
3k
views
Why do some common traceroute implementations default to using UDP probes?
I was recently troubleshooting a network connectivity meta-problem, in that I knew a given destination was reachable, but I was not able to demonstrate that with traceroute because the path went cold ...
- 869
4
votes
1
answer
7k
views
ICMP type 3 code 1 and 7, what is the diference?
What exactly is the difference between ICMP type 3 code 1 and code 7 messages? By reading their descriptions they seem to be used for the same purpose. I am trying to understand when a router will ...
- 158
1
vote
1
answer
2k
views
ICMP messages used by ping
I am studying about ICMP procotol and the ping program that uses ICMP messages. But I am not sure which ICMP messages are exactly used by the ping program
I know that
echo reply
echo request
time ...
- 113
10
votes
3
answers
22k
views
Traceroute Over TCP vs UDP
For what purpose would one wish to send traceroute over TCP rather than UDP? What advantages/disadvantages are there in doing so? I know that traceroute normally uses UDP ICMP "echo" packets while ...
- 953
2
votes
1
answer
196
views
Is there ever a scenario where there would be a 0 length response to an ECHO?
I'm attempting to utilize the flow probe argus to determine "node liveliness"/reachability.
I am currently working on handling ICMP status, but would like to derive a method to determine if a ping "...
- 135
6
votes
1
answer
716
views
IPv6 replacement for ICMP timestamp
Does any standard IPv6 protocol has anything analogous to an ICMP timestamp message?
- 407
3
votes
1
answer
472
views
ICMP redirect message
As I understand ICMP redirect message is sent to host to "shorten" the routing path of the packet .
If i have the example here and the path from host in network 1 to network 3 is equal using both R2 ...
- 135