Groups > comp.os.linux.networking > #4651

Re: ftp,ssh,http blocked by ISP?

From	William Unruh <unruh@invalid.ca>
Newsgroups	comp.os.linux.networking
Subject	Re: ftp,ssh,http blocked by ISP?
Date	2020-07-19 17:35 +0000
Organization	A noiseless patient Spider
Message-ID	<rf209c$h8k$1@dont-email.me> (permalink)
References	<reuqg2$cvg$1@dont-email.me> <rf1gma$u6u$1@news1.tnib.de>

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On 2020-07-19, Marc Haber <mh+usenetspam1118@zugschl.us> wrote:
> Bob Tennent <rdtennent@tennent.ca> wrote:
>>For years I've used port-forwarding in my router to allow
>>external access to ftp, ssh, and http servers. Recently,
>>this no longer works. The servers are running normally and
>>can be accessed internally. I can even access them via the
>>router IP address, showing that port-forwarding is still
>>working. I've also tried port-fowarding and DMZ in the
>>modem, to no avail. So my conjecture is that the ISP has
>>decided to block packets it considers unworthy before they
>>reach the modem.
>>
>>Is this at all likely? How can I test/confirm the
>>conjecture? If it is confirmed, what can I do? Needless to
>>say, ISP "technical support" has so far been useless.
>
> Most likely they have moved your setup to something that is called
> "Carrier Grade NAT" which makes it impossible to reach your home setup
> from the Internet if none of your internal systems has actively
> initiated the connection. This saves precious IPv4 addresses but makes
> it impossible to run servers at your home.
>
> The same way you have established the port-forwarding in your router,
> they would have to establish port-forwarding from their Carrier Grade
> NAT device to your router. Nearly no ISP actually offers this service.
>
> This is what we got (and deserved!) by ignoring the IPv4-Internet
> getting full and missing the IPv6 in the last two decades. And now
> we're complaining about that.
>
> Maybe if you yell loud enough they might move you back to an
> exclusively assigned IPv4 address (some ISPs in Germany actually do
> that on request), but you might be out of luck here.

IF that is the case, then you could establish an ssh tunnels to a
computer which was outside ISP domain. Unfortunately, AFAIK the tunnel
is port specific. Ie, only one port per tunnel. So if you want to tunnel
ssh, ftp, http you would have to have three tunnels AFAIK. 
You could use autossh to do so (which would reestablish the tunnel if
for some reason the ssh link died).

Anyone wanting to get at your location would then have to connect to the
appropriate port on the remote machine which would send the information
over the ssh link to your machine. 

If you have no machine outside the ISP domain with its own valid
address, then you would be out of luck. 
By looking at the address assigned to your router by the ISP you can
tell if they are NATing you. If it is an address in the ranges
10.x.x.x, 192.168.x.x, 172.172.16.0.0 – 172.31.255.255, then that is
what they are doing to you. If it is a valid public address, then not. 

If you can log onto your router, then you can usually find out what its
outside address is. (In this case the trick of going to one of the sites
that tells you where your connection came from would not work since all
it would know is that it came from the ISP, not which of the
computers/routers it came from)

>
> Greetings
> Marc

Thread

ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-18 12:38 +0000
  Re: ftp,ssh,http blocked by ISP? Dan Purgert <dan@djph.net> - 2020-07-18 14:59 +0000
    Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-18 15:15 +0000
      Re: ftp,ssh,http blocked by ISP? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-18 20:01 +0300
        Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-18 22:06 +0000
    Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-18 16:35 +0000
  Re: ftp,ssh,http blocked by ISP? Ken Hart <kwhart1@frontier.com> - 2020-07-18 11:12 -0400
    Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-18 16:44 +0000
  Re: ftp,ssh,http blocked by ISP? John McCue <jmccue@jmclin1.hsd1.ma.comcast.net> - 2020-07-18 16:33 +0000
  Re: ftp,ssh,http blocked by ISP? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2020-07-18 13:26 -0400
    Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-18 17:56 +0000
      Re: ftp,ssh,http blocked by ISP? Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2020-07-18 14:36 -0400
        Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-18 19:06 +0000
          Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-18 22:13 +0000
            Re: ftp,ssh,http blocked by ISP? "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2020-07-18 19:36 -0400
              Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-19 12:56 +0200
                Re: ftp,ssh,http blocked by ISP? Johann Beretta <beretta@nun-ya-bizness.com> - 2020-07-28 21:26 -0700
                Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-29 10:40 +0200
                Re: ftp,ssh,http blocked by ISP? Johann Beretta <beretta@nun-ya-bizness.com> - 2020-08-01 21:22 -0700
                Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-08-02 13:16 +0200
                Re: ftp,ssh,http blocked by ISP? Johann Beretta <beretta@nun-ya-bizness.com> - 2020-08-03 13:57 -0700
                Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-08-03 23:07 +0200
            Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-19 01:40 +0000
              Re: ftp,ssh,http blocked by ISP? "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2020-07-18 22:10 -0400
              Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-19 12:59 +0200
  Re: ftp,ssh,http blocked by ISP? Giovanni <lsodgf0@home.net.it> - 2020-07-19 10:10 +0200
  Re: ftp,ssh,http blocked by ISP? Marc Haber <mh+usenetspam1118@zugschl.us> - 2020-07-19 15:09 +0200
    Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-19 17:35 +0000
      Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-20 02:33 +0000
        Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-20 02:55 +0000
        Re: ftp,ssh,http blocked by ISP? "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2020-07-19 23:32 -0400
        Re: ftp,ssh,http blocked by ISP? "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2020-07-19 23:46 -0400
          Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-20 06:01 +0000
            Re: ftp,ssh,http blocked by ISP? "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2020-07-20 20:16 -0400
            Re: ftp,ssh,http blocked by ISP? Johann Beretta <beretta@nun-ya-bizness.com> - 2020-08-01 21:24 -0700
        Re: ftp,ssh,http blocked by ISP? Giovanni <lsodgf0@home.net.it> - 2020-07-20 09:10 +0200
          Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-20 11:31 +0000
            Re: ftp,ssh,http blocked by ISP? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-20 17:49 +0300
              Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-20 15:32 +0000
                Re: ftp,ssh,http blocked by ISP? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-20 21:01 +0300
                Re: ftp,ssh,http blocked by ISP? Bit Twister <BitTwister@mouse-potato.com> - 2020-07-20 13:04 -0500
            Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-20 20:11 +0000
              Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-20 20:42 +0000
                Re: ftp,ssh,http blocked by ISP? William Unruh <unruh@invalid.ca> - 2020-07-20 21:11 +0000
                Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-21 01:52 +0000
                Re: ftp,ssh,http blocked by ISP? dyrmak <dyrmak@quelite.terre.invalid> - 2020-07-21 08:35 +0000
  Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-21 10:34 +0000
    Re: ftp,ssh,http blocked by ISP? Giovanni <lsodgf0@home.net.it> - 2020-07-21 13:48 +0200
      Re: ftp,ssh,http blocked by ISP? Bob Tennent <rdtennent@tennent.ca> - 2020-07-21 13:35 +0000
        Re: ftp,ssh,http blocked by ISP? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-21 16:03 +0200

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