Network monitor software

[Dick Berg]

Can anyone recommend a (free) app that I can use on my Win7 computer that will enable me to monitor the network traffic to/from all the other computers and devices (9 of them) on my LAN?

I've been experiencing really slow network downloads lately - for example, it takes many minutes to connect to Facebook, or YouTube videos constantly stop while waiting for more of the stream of video, and I'm interested in trying to see where (or if?) my LAN traffic is bottled up. Is this one of my children playing Blockland or Minecraft online? or downloading Netflix videos? or playing DS or Wii games with someone overseas... I have nominally a T1 connection. I don't care about the content so much as I'm looking to measure the volume rate of traffic and where the bottleneck(s) are. It'd be nice if there were a graphical history showing the traffic to each network node over time.

Thanks.

[Bob Denny]

Yes indeed!

TCP View monitors your open connections and optionally unconnected endpoints, Very useful for seeing what programs use what ports, and who is connected to (some) of them.

For a full-up packet tracer and monitor, I highly recommend Microsoft Network Monitor. It has a bit of a learning curve, but it will organize your traffic into "conversations", separating traffic between each pair of endpoints. You can see not only the volume of traffic, but the timing and contents of each packet. It has parsers to "pretty print" zillions of different data types in the packets (HTTP, FTP, SMTP, ICMP...) as well as both the TCP and IP headers, etc. etc. There's so much there. I live and die by Netmon when working on the web and FTP servers, etc.

Alternate Netmon download location

[John Winfield]

Netmon is ok, but IMO the best of the free network analyzers is WireShark (was Ethereal)

http://www.wireshark.org/

I've used this at work for years through several companies The protocol decode across the board is the best I've found.

John

[Dick Berg]

Thanks, John and Bob,

Bob, I've installed Netmon and I am struggling (though winning, I think) with getting it to work the way I'd like it to work. Capturing isn't the problem - it's displaying the right stuff while discarding/disregarding the minutiae.

John, I will try WireShark presently.

What I'd really like to have is an accumulating histogram of the packet traffic that comes and goes between each of the nodes on my LAN and the Internet. I don't care about all the other traffic that's going on between my LAN nodes. (Someone(s) in my house is using most of the bandwidth (!!) and I'm going to find out who -- heh! heh! We're still waiting for FIOS in our neighborhood.)

[John Winfield]

Hmm, having now read your first post I don't think either tool will do what you're after, since they can't see traffic to or from other machines on a switch.
Your best bet to see what is consuming the internet bandwidth would be to see if your router has any monitoring capabilities. The open source ddwrt firmware does if you have a compatible router, although that may be a bigger project than you were looking for

John

[Dick Berg]

Hey John,

NetMon can certainly see packets that go between the router and any of the devices on the LAN and the WAN. And it can also filter on HTTP GETs and the like, so it has the capability in tabular form to see what I'm looking for. Graphing the table data is not part of the suite of its tools (as far as I can tell yet).

WireShark looks interesting, but I've only gotten as far as seeing that it can capture packets back and forth from the local node. It looks like capturing traffic on a remote computer is possible, but it requires installing wnpcap (whatever it's called) on each node which is cumbersome. There is a graphing tool in the package. It looks like it's only possible to capture traffic only between two nodes at a time.

My strategy up to now has been to disable each node individually (via MAC authentication) and sequentially at the router, to see how traffic and throughput changes, but that raises lots of screams from my three teenagers, as in "Daddy, there's something wrong with the Internet!!!!"

My router is a Westell 7500. Its diagnostic tools are pretty feeble.

Thanks for your help and comments.

[Marco Lorenzi]

but that raises lots of screams from my three teenagers, as in "Daddy, there's something wrong with the Internet!!!!"

Three teenager sharing the same connection at home ?? I am surprised you still have same bandwidth left to connect to your observatory

I have also the need to find a network monitor software, were I have my observatory we are sharing the same line between few people and now we start having the need to understand who is using what and maybe (it would be great!) limiting the bandwidth and data transfer between different PCs.
Is there any software doing this for domestic lines?

Clear Skies
Marco