[GLLUG] tcpdump

[Marr]

On Sat, 13 Aug 2016 15:13:05 -0500
Chick Tower <c.e.tower at gmail.com> wrote:

> I upgraded to the new Slackware (14.2), and it has a newer version of 
> Firefox (45.3.0, after one upgrade).  I'm on dial-up, and as soon as
> I fire up Firefox the modem lights start flashing away, and my
> effective modem speed seems to be at least halved.  So, in addition
> to trying other, less "chatty" browsers, I wanted try and analyze the
> traffic to see if I could block it or modify Firefox to stop it.
> 
> Has anyone used tcpdump?  I was looking at wireshark, but it said it
> was a graphical version of tcpdump, and tcpdump is already installed. 
> However, when I run it, even according to the examples, it doesn't
> catch anything at all.  I've tried the following commands, as root:
> 
> tcpdump host <myhostname>
> tcpdump -v host <myhostname>
> tcpdump -v host <myfullyqualifiedhostname>
> tcpdump -v host localhost
> 
> Does anyone have any tips?

Chick,

Two things come to mind, FWIW.

(1) I prefer 'iptraf' (run as 'root', e.g. in a 'konsole' window
because it uses ncurses [think "crude GUI, like the Slackware
installer"]). Comes pre-installed with the full Slackware 14.2. I've
used 'tcpdump', but I feel more in control with 'iptraf', although I
don't use either app that often.

(2) It might be wise to fire up GKrellM (performance meters, for those
on this list unfamiliar with it) and configure it (F1 hotkey) to monitor
PPP traffic, so that you can see things in realtime.

As I was configuring Slackware64 14.2 on my main PC the other day, I
hadn't yet configured all the Firefox add-ons and was semi-horrified at
the amount of crap on most webpages.  I guess it's been 2.5 years since
I configured Firefox from scratch (last time I installed Slackware on
the main PC) and I'd forgotten the horror of the unfiltered
Internet. :^)

I'm pretty sure you're already running Privoxy (like me).  I also
installed these Firefox addons: NoScript, RequestPolicy, uBlock Origin,
Flashblock, and a few others, but Privoxy with those 4 should be a big
help in cutting webpage load times.

HTH...

Regards,
Bill