Re: question about network connections
On Sat, 26 Oct 2019 12:27:54 +0100
mick crane <mick.crane@gmail.com> wrote:
> On 2019-10-26 12:19, Joe wrote:
> > On Sat, 26 Oct 2019 11:57:19 +0100
> > mick crane <mick.crane@gmail.com> wrote:
> >
> >> hello,
> >> what tests can I do to find out what is happening with internet
> >> connection ?
> >> I have pfsense as router connecting to ISP's broadband box.
> >> I think pfsense does that DHCP but also I might have names to
> >> ipadresses in host files but just for local network addresses.
> >> I have debian apache on local network offering a page with links
> >> like my bookmarks
> >>
> >> Problem is there is one site that sometimes it loads sometimes it
> >> times out.
> >
> > That has something of the sound of DNS, though bear in mind that
> > some sites do drop out/get busy for a few seconds. I've known
> > Firefox to tell me that it can't find Google, and an immediate
> > retry works.
> >> I connect from windows-> apache web page of links-> internet site.
> >> I've run wireshark in the past but have no idea what to make of the
> >> results.
> >>
> >> What can I run and where to see where is not working ? If is me or
> >> them.
> >
> > Start with DNS. What DNS does the workstation use? Try something
> > different. If it's using your router or ISP, try OpenDNS or
> > something else outside the ISP's network.
> >
> > Also try traceroute to the offending site at various times to see if
> > you get a consistent time or whether there is a blockage somewhere.
> >
> > As you say, Wireshark can be difficult, though it has very powerful
> > filtering once you know what you're looking for. Again look for
> > TCP/53 outgoing and replies.
> >
> > A simpler alternative for some jobs can be the firewall. I'm still
> > on iptables, and if I'm having trouble with a particular type of
> > packet, I'll make (or more likely, reenable) a couple of logging
> > rules to give me at least a basic understanding of what is going in
> > and out.
>
> I changed the DNS servers on the pfsense from the ISPs to 1.1.1.1,
> 1.0.0.1 and make no difference.
> What confuses me is how wireshark on one PC with one network card can
> capture traffic on network card on another PC
>
>
Naughty promiscuous mode, though I think you have to be root to do that.
https://en.wikipedia.org/wiki/Promiscuous_mode
--
Joe
Reply to: