[Durham] What is eating up my bandwidth?

David Beer david at thebeerfamily.com
Mon Jul 8 09:44:29 UTC 2013

Hi Dougie

I would start but turning of as much as possible and checking the 
network activity, this sounds rather odd. I would also check previous 
months usage before it started going up and maybe even check with Zen. 
Zen should also have some tracking monitoring  etc in place if they have 
caped your limit.

Just my thoughts.


On 07/07/13 15:42, Dougie Nisbet wrote:
> I'm running out of ideas. Short of going round and switching things 
> off one by one, which might not be such a bad idea.
> I'm with Zen and get 100GB/month broadband allowance. For the past few 
> months I've noticed that it's creeping up, and recently I've ran out. 
> In fact I ran out at 20 minutes to midnight on the 30th June and 
> decided I could last 20 minutes without internet. Right now I'm up to 
> 27GB used, and it's only the 7th of the month! Where's it all going? 
> I've commented out the obvious culprits (get-iplayer for example), and 
> I'm not too worried about uploads as they're not included in the 
> allowance.
> The next step was to look at ways of seeing where it's being used. 
> I've looked at lots of utilities for showing where bandwidth is being 
> used. Currently I've got iftop running:
>     iftop  -F
> which seems to be doing what I want - showing stuff going into and out 
> of the homelan, but not internal traffic.
> Of course, I soon hit upon the problem of not seeing all traffic. 
> After googling for tools and advice I realised that switches are too 
> good at being switches, so I bought one of these (a Netgear GS510E 
> 5-port switch):
> http://www.amazon.co.uk/gp/product/B002U08F2S/ref=oh_details_o09_s00_i00?ie=UTF8&psc=1 
> that allows port mirroring on port 5. I've got my Linux desktop in 
> port 5 and all other ports mirrored to it.
> I really thought that would do the trick and I'd see some smoking gun 
> - but alas no. The bandwidth still gets eaten up and even though I've 
> been running iftop for days it's not really showing anything of 
> concern. I wonder sometimes if things are blipping, briefly using lots 
> of bandwidth then terminating - I've a feeling iftop wouldn't show 
> that unless I was staring at it at the time.
> I suppose there's wifi. My router is wireless and we have two iphones 
> and two ipads, although we connect to the other (5) WAPs too. Perhaps 
> I could disable the wifi on the router, forcing it to go through the 
> WAPs, which would then, in theory, show up as it'd have to go via the 
> Netgear switch.
> Dunno. Anyone any ideas on how to problem solve this? I know I can 
> just turn things off but this would be a) inconvenient and b) an 
> admission of defeat. I'd rather track the culprit down.
> Dougie
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