Wireshark · Wireshark-users: Re: [Wireshark-users] Troubleshooting slow network

[Cheikhou Dramé <dramecheikhou@xxxxxxxxx>]

Le 02/12/2012 22:03, Martin Visser a écrit :

Just to be clear, 2 packets, 1ms apart IS 1000 pps - just not typically valid for extrapolation that might make you t think the network is busy

Regards, Martin

MartinVisser99@xxxxxxxxx

On 3 December 2012 08:59, Martin Visser <martinvisser99@xxxxxxxxx> wrote:

Cheikhou,

A couple of things.

1. The packets per second column is an anomaly in this case. You only have a few packets (most show 2). So the calculation of pps is really going to be skewed here. (2 packets very close to each other, say 1ms apart, would be interpreted as 1000 pps - clearly not right). 

2. This isn't going to tell you anything about Internet usage. You are only seeing the "leaked" traffic from multicasts to your port.

 You will need to get someway of getting the traffic on the Internet link. There are a few switches available for only a few hundred dollars that can do port-mirroring. Another way is to set up a PC (Linux is best) in bridge mode, and run Wireshark on this as it sees the traffic go by.

Regards, Martin

Regards, Martin

MartinVisser99@xxxxxxxxx

On 3 December 2012 00:57, Cheikhou Dramé <dramecheikhou@xxxxxxxxx> wrote:

Le 02/12/2012 04:04, Martin Visser a écrit :

Multicast on UDP port 1900 will be SSDP or now known as UPnP, Universal Plug and Play. This is just a control protocol used to discover services on the network. The traffic you see might be PC or the like advertising they have Audio/Video available, or your router advertising that a PC can use it to open up it's firewall (for games/bittorent etc).

As it is really just a control protocol, not for sending actual data payloads, 15K packets/sec seems very high. Are you sure this is correct. You can identify the source from the source address - which will be unique on your network - or probably in the packets themselves. (You might need to set UDP port 1900 to be decoded as SSDP).

When you say the network is "slow" you need to be more specific. Is this only to/from the Internet or also LAN to LAN?

Also don't forget that when you do a Wireshark capture on just a regular switch port - you will ONLY see your own traffic and multicast/broadcast traffic. Hence you might not be seeing the greater proportion of traffic in your network. To this you need to enable port-mirroring on your switch and use Wireshark in promiscuous mode.

Regards, Martin

MartinVisser99@xxxxxxxxx

On 1 December 2012 04:43, Cheikhou Dramé <dramecheikhou@xxxxxxxxx> wrote:

port 1900

thanks for your reply. My switches can't do port-mirroring.As seen in the file i have join , you can see the traffic wich i'm talking about , the network is slow just from and to  the internet.

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Hello , I have setup the firewall-transparent proxy working as gateway on centos 6 and used wireshark to capture 140megabits of data.The files joined is the expert composite analyse resume window. I noticed  that most of the errors come from 2 Macbook PC running software like bittorent , dropbox and my ldap/samba server wich act a PDC on my LAN. I have also search in the web for more informations about that.My switchs seems to be incompatible with some devices using gigabit/ethernet connexions.

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