cronjob to check network traffic packet

[Fauziah Mahdan]

Hi all,
What is the command to set cronjob to capture into file the network traffic packet from one server to another server?

I was inform to use
1) trace route
2) ping
3) netstat

Which one is better and what is the full command?

Thanks,
Fauziah

[Steven E. Protter]

Shalom Fauziah,

None of the above.

tcpdump is the best tool to look at a network packet.

I'd need to know a lot more about what you want to know to give a command.

SEP

[Fauziah Mahdan]

The application vendor claim that there is network issue that cause their application to hang and sometimes system crash.
They ping and found some packet loss but it was intermittently. So I have to create cronjob to check the traffic.
Sometimes when their application up we do find source quench received error which is I think not due to the network but more on the server cannot cope too many process request from the application.
So pls advise

[Wouter Jagers]

Hi,

You are right about the source quench.

You can have the ping command send out a fixed number of packets with the -n parameter:

# ping somehost -n3
--> will perform 3 'probes' and exit.

With the -I option (capital i) you can decide how many seconds the machine should wait between two probes:

# ping -I 10 somehost -n 60
--> would do 60 pings, waiting 10 seconds between each.

Traceroute is a command which sends out the same 'ping packets', but with different TTL (time to live) values. This way you can see all machines involved in getting your packet there + the time it took to get to each of these 'hops'. Syntax is straightforward:

# traceroute somehost

Good luck finding out the problem !

Cheers,
Wout

[Yogeeraj_1]

Hi Fauziah,

According to me, the first step would rather be determine if there are any bottleneck at the server level - network.

You can use Glance to view the information online or configure mwa to generate an appropriate report which will show the network utilisation for a period range.

Troubleshooting the network between the client and the server would be more difficult. You may wish to review the switch, router (if on a WAN) logs as well.

hope this helps too!

kind regards
yogeeraj

[Fauziah Mahdan]

Hi all,
2 db server connected to 3 app server via websphere act as laod balance then to 1 webserver (cannot imagine what happen when the webserver down).
As I mention the app vendor claim they server/system hang or crash maybe due to network. I have run cronjob for top command to check the cpu utilization.
so now cronjob on network site.
Wouter Jagers
I have done ping command so next is the traceroute. Will try.

Yogeeraj
Ungortunately vendor did not puchased the glance license for this software so I just run top, vmstat and netstat command to check the cpu utilization.

Thanks all.

[Fauziah Mahdan]

Hi all,
2 db server connected to 3 app server via websphere act as laod balance then to 1 webserver (cannot imagine what happen when the webserver down).
As I mention the app vendor claim they server/system hang or crash maybe due to network. I have run cronjob for top command to check the cpu utilization.
so now cronjob on network site.
Wouter Jagers
I have done ping command so next is the traceroute. Will try.

Yogeeraj
Unfortunately vendor did not puchased the glance license for this software so I just run top, vmstat and netstat command to check the cpu utilization.

Thanks all.

[Fauziah Mahdan]

Already purchase the glance software but not yet install in some of the servers.
Will downlaod and install it later.