Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

How to  sniff packets from router

Posted on 2006-06-09
8
Medium Priority
?
1,801 Views
Last Modified: 2013-12-07
What is the best way to look at real time traffic on you r router?? Can this be done with Linux/Unix? IS there some kind of command line tool to do this.

Thanks


0
Comment
Question by:andrew_89
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
8 Comments
 
LVL 1

Author Comment

by:andrew_89
ID: 16875017
Also how would you re-route traffic say for ftp to your secondary router to alleviate bandwidth consumption on the primary router?
0
 
LVL 3

Expert Comment

by:Tony Gimenez
ID: 16875188
http://www.ethereal.com

Its for Windows and Linux and its free!
0
 
LVL 3

Expert Comment

by:Tony Gimenez
ID: 16875211
If you need other programs for similar uses this should help
http://www.google.com/search?hl=en&lr=&q=real+time+network+monitoring&btnG=Search

0
Survive A High-Traffic Event with Percona

Your application or website rely on your database to deliver information about products and services to your customers. You can’t afford to have your database lose performance, lose availability or become unresponsive – even for just a few minutes.

 
LVL 57

Expert Comment

by:giltjr
ID: 16875342
What is the router connected to?  If it is a switch, then you need to have a managed switch that you can mirror the port that the router is connected to, that is you tell the switch to send a copy of all data that is going to or coming from port "A" to port "B"  Then you connect a computer to port "B" that has packet caputer software (like Ethereal).

That I am aware of I don't know of away to route traffic based on the application (ftp, http, telnet).  Routing is based on destination IP address.  Do you want to route all FTP traffic, or say ftp traffic from a specic host?  You should just change that hosts  default route.  Or, you could setup a ftp proxy server and have its default route be your "secondary" router.

However, in order for this to work, not only would you need a secondary router, you would need a secondary connection to the Internet.  Wouldn't it be less expensive to just increase the bandwidth on the primary connection?
0
 
LVL 8

Expert Comment

by:ragnarok89
ID: 16875804
You can monitor the amount of traffic going through a switch using Getif or a similar program that uses SNMP. This program can tell you (for example) the number of packets sent or received on a particular interface.

In order to see inside each packet, you will need a packet analyser such as ethereal, which can examine the headers and data inside each packet.

In order to route traffic, you will need a router with which you can create a port forwarding rule. So any traffic received for port 22 (ftp) would be directed to a specific IP address on your internal network - like your ftp server.
0
 
LVL 2

Expert Comment

by:Dazm
ID: 16875915

Try this easy to use program
"Ether Detect Packet Sniffer"
http://www.etherdetect.com

Maybe not the best, But truly the best : )
Is so easy that i don't have to tell you nothing else here.

Try it and let me know.
0
 
LVL 11

Accepted Solution

by:
grsteed earned 2000 total points
ID: 16877416
"Also how would you re-route traffic say for ftp"

You don't mention what kind of routers you have but if they are Cisco you may be able to use Policy Based Routing to do this. (other routers support this as well) It still depends on your topology.

Basically Policy Based Routing uses access lists and route-maps to make routing decisions. If you use Extended access lists, the decision could be based on TCP ports, along with Source and Destination. It doesn't control the destination of a packet, but can control the path it takes.  

Here's a few links if you want to read more.

http://www.21stcenturyarticles.com/Article/Cisco-CCNP---BSCI-Exam-Tutorial---Introduction-To-Policy-Routing/580
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt2/1cfindep.htm#wp1001398
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt1/qcfpbr.htm

 
Cheers,

Gary

0
 
LVL 2

Expert Comment

by:Psyco_666
ID: 16884517
If you dont have a managed switch you could replace the cable from your router to your internal network with 2 cables and a 4 port hub in between. This way you can plug in an ethereal laptop in any time to check on traffic loads. Only really works if you have a one in one out setup.

0

Featured Post

Plesk WordPress Toolkit

Plesk's WordPress Toolkit allows server administrators, resellers and customers to manage their WordPress instances, enabling a variety of development workflows for WordPress admins of all skill levels, from beginners to pros.

See why 2/3 of Plesk servers use it.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this article, I am going to show you how to simulate a multi-site Lab environment on a single Hyper-V host. I use this method successfully in my own lab to simulate three fully routed global AD Sites on a Windows 10 Hyper-V host.
This article is in regards to the Cisco QSFP-4SFP10G-CU1M cables, which are designed to uplink/downlink 40GB ports to 10GB SFP ports. I recently experienced this and found very little configuration documentation on how these are supposed to be confi…
Michael from AdRem Software explains how to view the most utilized and worst performing nodes in your network, by accessing the Top Charts view in NetCrunch network monitor (https://www.adremsoft.com/). Top Charts is a view in which you can set seve…
In this brief tutorial Pawel from AdRem Software explains how you can quickly find out which services are running on your network, or what are the IP addresses of servers responsible for each service. Software used is freeware NetCrunch Tools (https…

715 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question