Linux and ICMP timestamp requests. Post: 40477

10 More Discussions You Might Find Interesting

1. IP Networking

icmp

how i can send the big icmp packets to the another ip for loose connection ....or how he can loose

2. UNIX for Advanced & Expert Users

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!! :)...

3. UNIX Desktop Questions & Answers

How can I see current browser requests? (Firefox on Ubuntu Linux)

I'm not sure if this is the right forum (if there's a better forum elsewhere, then I would be grateful for any pointers), but anyway: I am using Firefox 2.0.0.14 on Ubuntu 7.10 for day-to-day graphical webbrowsing. I sometimes find that some websites take a long time to answer certain requests...

4. IP Networking

Ping ICMP

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

5. Solaris

ICMP Net Unreachable from gateway

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...

6. UNIX for Dummies Questions & Answers

Log file for icmp requests

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.

7. Shell Programming and Scripting

ICMP for limited time

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

8. Shell Programming and Scripting

To check timestamp in logfile and display lines upto 3 hours before current timestamp

Hi Friends, I have the following logfile. Currently time in india is 07/31/2014 12:33:34 and i have the following content in logfile. I want to display only those entries which contain string 'Exception' within last 3 hours. In this case, it would be the last line only I can get the...

9. IP Networking

Routing ICMP echo requests

I have an application where I need to configure a router to pass through ping requests (ICMP type http://www.dd-wrt.com/phpBB2/images/smiles/icon_cool.gif through to the LAN port. I have a Linksys WRT54GS with tiny DD-WRT V24 SP2 installed. I am adding the following iptables rules: iptables -t...

10. IP Networking

iptables - formatting icmp rules

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...

LEARN ABOUT LINUX

clockdiff

CLOCKDIFF(8)						 System Manager's Manual: iputils					      CLOCKDIFF(8)

NAME

       clockdiff - measure clock difference between hosts

SYNOPSIS

       clockdiff [-o] [-o1] destination

DESCRIPTION

       clockdiff  Measures  clock difference between us and destination with 1 msec resolution using ICMP TIMESTAMP [2] packets or, optionally, IP
       TIMESTAMP option [3] option added to ICMP ECHO.	[1]

OPTIONS

       -o     Use IP TIMESTAMP with ICMP ECHO instead of ICMP TIMESTAMP messages. It is useful with some destinations, which do not  support  ICMP
	      TIMESTAMP (f.e. Solaris <2.4).

       -o1    Slightly	different  form  of  -o,  namely it uses three-term IP TIMESTAMP with prespecified hop addresses instead of four term one.
	      What flavor works better depends on target host. Particularly, -o is better for Linux.

WARNINGS

       o Some nodes (Cisco) use non-standard timestamps, which is allowed by RFC, but makes timestamps mostly useless.

       o Some nodes generate messed timestamps (Solaris>2.4), when run xntpd. Seems, its IP stack uses a corrupted clock source, which is synchro-
	 nized	to  time-of-day  clock periodically and jumps randomly making timestamps mostly useless. Good news is that you can use NTP in this
	 case, which is even better.

       o clockdiff shows difference in time modulo 24 days.

SEE ALSO

       ping(8), arping(8), tracepath(8).

REFERENCES

       [1] ICMP ECHO, RFC0792, page 14.

       [2] ICMP TIMESTAMP, RFC0792, page 16.

       [3] IP TIMESTAMP option, RFC0791, 3.1, page 16.

AUTHOR

       clockdiff was compiled by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>. It was based on code borrowed from BSD timed daemon.	It  is	now  main-
       tained by YOSHIFUJI Hideaki <yoshfuji@skbuff.net>.

SECURITY

       clockdiff requires CAP_NET_RAWIO capability to be executed. It is safe to be used as set-uid root.

AVAILABILITY

       clockdiff  is  part  of iputils package and the latest versions are  available in source form at http://www.skbuff.net/iputils/iputils-cur-
       rent.tar.bz2.

iputils-101006							   12 April 2011						      CLOCKDIFF(8)

10 More Discussions You Might Find Interesting

1. IP Networking

icmp

Discussion started by: seccom

2. UNIX for Advanced & Expert Users

ICMP Echo-Request

Discussion started by: ilmora

3. UNIX Desktop Questions & Answers

How can I see current browser requests? (Firefox on Ubuntu Linux)

Discussion started by: ropers

4. IP Networking

Ping ICMP

Discussion started by: vasanthan