I have an application where I need to configure a router to pass through ping requests (ICMP type through to the LAN port. I have a Linksys WRT54GS with tiny DD-WRT V24 SP2 installed. I am adding the following iptables rules:
The intent is that the first rule will change an incoming echo request destination to the unit on the LAN which I want to receive the ping request.
The second rule allows the modified echo request to pass through the FORWARD table.
And the last one allows the modified echo request to pass through the POSTROUTING table.
When I send a ping to the router with four tries, I get no pings out the LAN. Using iptables -L -v -n I can see were rule #1 passes one packet (but not four), rule #2 passes four packets (good!) and rule #3 passes 1 packet.
At this point I am at loss as to why this is not working. Can someone help me out here?
Last edited by Don Cragun; 07-10-2015 at 04:56 PM..
Reason: Add CODE tags.
Hi There,
I am looking to disable ICMP timestamp requests and ICMP timestamp replies on my Linux server version 8. Can someone please tell me the simplest way to do this? I know a command to disable all ICMP traffic but this I have been told will cause many network problems which I... (2 Replies)
Hello! I'm in extra urgent need to have a program that sends a series of ICMP echo requests over the network to a specified host and waits until the last echo reply is received.
I know little about socket-programming (in particular I've never dealt with icmp sockets) that's why i'm desperate!! :)... (5 Replies)
Dear,
I want to perform a plotting using xgraph, and the plotting data (ping.txt) is as below. For the graph I just want to plot the time for x-axis (line count) and the RTT for y-axis (time in ms). Below are script i write for that purpose but it seen did not work. Any guide for me because i... (1 Reply)
Hi All,
How to disable ICMP time stamp request and time stamp reply of a machine?
How to test this feature from remote machine?
Please reply back
Vasanth (2 Replies)
Hi
I am trying to perform a jumpstart with values below
client sf440-003 - ip x.x.133.2
jumpstartserver zeus - ip x.x.133.19
The jumpstart tftp works as it should, I boot the machine with boot net - install etc. But when it should do a PORTMAP it fails with ICMP error.
Any ideas... (2 Replies)
Hi all,
I cannot reach my SERVER from my NetBackup server connect through SERVER_prv ("cannot connect to client")
My SERVER was Sun OS 5.8, below is the message i get when i ping my SERVER:
# ping 192.168.X.X or
# ping SERVER_prv
ICMP Net Unreachable from gateway 172.16.102.XXX
for... (3 Replies)
I'm not a unix expert so I need to ask what maybe a simple question to some. Is there a log file which records any icmp packets hitting the server? I ask, because I need to verify what the ip is from a server pinging mine. (3 Replies)
Hi,
I am using following command:
tcpdump -i eth1 icmp =8 >output.txt
i want this command to get execute for a minute only. How can we do this?
Thanks.
Please use code tags next time for your code and data. Thanks (2 Replies)
Hi, I am relatively new to firewalls and netfilter. I have a Debian Stretch router box running dnsmasq, connected to a VPN. Occasionally dnsmasq polls all of the desired DNS servers to select the fastest. When it does this it responds to replies of the non-selected DNS servers with a icmp type... (0 Replies)
Discussion started by: CrazyDave
0 Replies
LEARN ABOUT ULTRIX
ping
ping(8) System Manager's Manual ping(8)Name
ping - send ICMP ECHO_REQUEST packets to network hosts
Syntax
/etc/ping [ options ] host [ datasize [ npackets ]]
Description
The DARPA Internet is a large and complex network of hardware connected together by gateways. The command utilizes the ICMP protocol's
mandatory ECHO_REQUEST datagram to elicit an ICMP ECHO_RESPONSE from a host or gateway. ECHO_REQUEST datagrams (pings) have an IP and ICMP
header, followed by a struct timeval, and then an arbitrary number of pad bytes used to fill out the packet. The length of the default
datagram 64 bytes, but this may be changed using the command-line option.
Typing ``ping host'' without any options will either report ``host is alive'' or ``no answer from host''. To get more statistics use the
-l option or one of the other options.
When using for fault isolation, it should first be run on the local host to verify that the local network interface is up and running.
Then, hosts and gateways further and further away should be pinged. The command with options sends one datagram per second and prints one
line of output for every ECHO_RESPONSE returned. No output is produced if there is no response. If an optional npackets is given, only
that number of requests is sent. Round-trip times and packet loss statistics are computed. When all responses have been received or the
program times out with npackets specified, or if the program is terminated with a SIGINT, a brief summary is displayed.
Options-d Turns on SO_DEBUG flag on the socket.
-l Gives more statistics than if is used without options. Long output.
-r Bypasses the normal routing tables and sends directly to a host on an attached network. If the host is not on a directly-attached
network, an error is returned. This option can be used to ping a local host through an interface that has no route through it. For
example, after the interface was dropped by
-v Lists ICMP packets other than ECHO RESPONSE that are received. Verbose output.
Restrictions
This program is intended for use in network testing, measurement, and management. It should be used primarily for manual fault isolation.
Because of the load it could impose on the network, it is unwise to use during normal operations or from automated scripts.
See Alsonetstat(1), ifconfig(8c)ping(8)