On 26/04/2023 19:57, Jim Jackson wrote:

>>
>> 1) Pi only: add 'ipv6.disable=1' to end of line in /boot/cmdline.txt
>
> Just a small quibble - while the whole /boot/cmfline.txt thing is Pi
> specific, the ipv6.disable=1 kernel parameter setting should work on all
> Linux kernels.
>

Could be, no real reason to try it.

--
Chris Elvidge
England

Chris,

>> A new question though (if you don't mind) : I've been trying to disable
>> ipv6
>> too, and reading the man page for dhcpcd.conf I saw that I could use
>> "ipv4only".
>
> Try:
> noipv6rs
> noipv6

I tried both seperatily and together (even though the latter seems to includ
the former), but ifconfig still shows ipv6 adresses. :-\

> Have you looked at man dhcpcd.conf?

Thats pretty much the first thing I did after your suggestion to edit that
file. Its where I got that "ipv4only" thingy from (which doesn't work as
I imagine it would).

> Don't get too hung up on the raspbian/bullseye focus.
> dhcpcd configuration is dhcpcd configuration no matter which distro you're
> using.

I've got to take your word for that, as I do not (yet) posess that
knowledge - which is why I mentioned what my starting point is, so we would
be on the same page. Thank you for mentioning it.

> It seems there are 2 ways to totally disable ipv6

And thanks for those. I think I found those myself too, but didn't
actually
read them as it /looked like/ dhcpcd.conf had the means to gouvern them (and
assumed a similar problem as in regard to dhclient - looking at the wrong
thing)

But a bit of a bummer : I was assuming that I could disable it for one
interface, but keep it enabled for another.

Regards,
Rudy Wieser

Ahem A Rivet's Shot,

> What sort of ipv6 addresses ? If it is only link local ipv6
> addresses (starting fe80::) then they don't come from DHCPCD but from IPv6
> neighbour discovery and are probably quite hard to get rid of but they're
> only valid on a LAN segment so I wouldn't worry about them too much.

>> What sort of ipv6 addresses ? If it is only link local ipv6
>> addresses (starting fe80::)

it (eth1) is.

> then they don't come from DHCPCD but from IPv6 neighbour discovery and are
> probably quite hard to get rid

So every of those "noipv6" and "ipv4only" things in (man) dhcpcd.config are
fake ? They actually don't do squat ? That would perhaps have been a good
april
first joke, but not on any other day. :-(

> of but they're only valid on a LAN segment so I wouldn't worry about them
> too much.

:-) All computers on my LAN (and probably yours too) have local ipv4
adresses, but they can still connect to other computers all over the world.

The thing is that that I have multiple computers on my lan, and I don't want
to discover that one of them is using ipv6 - which I do not use and as such
have very little knowledge of - as a weakpoint to gain access to others.

Regards,
Rudy Wieser

On Wed, 26 Apr 2023 23:17:27 +0200
"R.Wieser" <address@is.invalid> wrote:

> So every of those "noipv6" and "ipv4only" things in (man) dhcpcd.config
> are fake ? They actually don't do squat ? That would perhaps have been
> a good april

Not at all, they control whether or not dhcpcd issues public IPv6
addresses. You get link local addresses without dhcpcd or anything other
than an IPv6 capable kernel.

The link local addresses that are provided by the kernel are
nothing more than a standard wrapper around the MAC and they really are
only valid on the LAN segment (same as the MAC) they cannot cross any kind
of router internal or external, unlike IPv4 private addresses which are by
convention not permitted to cross routers into the 'public internet' and
have been known to cross boundary routers in both directions.

I'm not sure it's possible to NAT IPv6 link local addresses, you'd
certainly have to work at it, by default there's no kind of NAT used for
IPv6 the addresses are either link local or public.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

Ahem,

>> So every of those "noipv6" and "ipv4only" things in (man) dhcpcd.config
>> are fake ? They actually don't do squat ? That would perhaps have been
>> a good april
>
> Not at all, they control whether or not dhcpcd issues public IPv6
> addresses. You get link local addresses without dhcpcd or anything other
> than an IPv6 capable kernel.

I realized only later that what you mention in that the last line could be
the case.

Do you happen to know if its possible and if so how to configure ipv6 to
/not/ to generate such a "link local address" and only expose an address if
provided thru dhcp (so it functions the same way ipv4 works and its a per
interface thing) ?

> unlike IPv4 private addresses which are by convention not permitted
> to cross routers into the 'public internet'

:-) Just send the request to the "default gateway" machine and it does some
NAT magic to get the request done using a "IPv4 private address" on the
internet regardless.

> and have been known to cross boundary routers in both directions.

Sort of. /Some/ "IPv4 private addresses" may go one way, /others/ may go
the other way. Which ones is under control of and has to be configured per
router.

> I'm not sure it's possible to NAT IPv6 link local addresses, you'd
> certainly have to work at it,

Do you know What would be the difference between ipv4 and ipv6 that would
make it especially hard to do for the latter ?

> by default there's no kind of NAT used for IPv6 the addresses are
> either link local or public.

Thats just because there are way more ipv6 IPs available than we currently
can use, and NAT-ing hem would (look to) be a bit silly - an exercise in
futility.

Regards,
Rudy Wieser

Chris,

> a) if using sysctl: put a file in /etc/sysctl.d/ containing
> net.ipv6.conf.all.disable_ipv6 = 1
> net.ipv6.conf.default.disable_ipv6 = 1
> net.ipv6.conf.lo.disable_ipv6 = 1

I've applied all three, and after rebooting looking at ifconfig I do not see
any ipv6 any more. Thank you.

One question though : The latter two entries seem to be subsets of the first
one. Is there something I'm missing or is this just a case of wearing a
belt /and/ suspenders ?

Regards,
Rudy Wieser

On 26/04/2023 20:00, Ahem A Rivet's Shot wrote:
> On Wed, 26 Apr 2023 19:14:46 +0100
> The Natural Philosopher <tnp@invalid.invalid> wrote:
>
>> But dhcp is only used at boot time normally.
>
> Either dhclient or dhcpcd should persist so that it can renew the
> lease when the time comes - try a ps -elf | grep dhclient or pgrep -lf
> dhclient.
>
Nope.
xxx@juliet:~/Desktop$ ps -elf | grep dhclient
0 S xxx 232070 232062 0 80 0 - 2259 pipe_w 09:27 pts/0
00:00:00 grep --color=auto dhclient
xxx@juliet:~/Desktop$ pgrep -lf dhclient
xxx@juliet:~/Desktop$

Nada.
What does persist its network stuff

$ ps -elf | grep net
1 I root 34 2 0 60 -20 - 0 - Apr19 ?
00:00:00 [netns]
4 S root 604 1 0 80 0 - 9996 - Apr19 ?
00:00:00 /usr/bin/python3 /usr/bin/networkd-dispatcher
--run-startup-triggers
0 S xxx 95676 1938 0 80 0 - 97033 poll_s Apr22 ?
00:00:00 /usr/libexec/gvfsd-network --spawner :1.7 /org/gtk/gvfs/exec_spaw/5

I conclude that in later versions of Mint desktop systems neither
dhclient nor dhcpd are used.

I have found the layer upon layer of obsolete and obsolescent networking
files to be a total pain to deal with.

And indeed even though my server is set to static IP address via
network manager it also has a ghost IP address assigned by DHCP. This
responds to pings and shows up on the router dhcp tables, but is
otherwise completely unused for anything

I have concluded that like so much software, Mint/Ubuntu/Debian is being
overwhelmed by the dreaded weed Creeping Featurism and and has been
debugged only insofar as to work for 'normal' situations, and underneath
is a BFM. A Bloody Fucking Mess, that like postscript and X windows has
been stabilised by the general principle of 'buggering around till it
sorta works'.

--
“The ultimate result of shielding men from the effects of folly is to
fill the world with fools.”

Herbert Spencer

On 26/04/2023 21:52, R.Wieser wrote:
> Chris,
>
>>> A new question though (if you don't mind) : I've been trying to disable
>>> ipv6
>>> too, and reading the man page for dhcpcd.conf I saw that I could use
>>> "ipv4only".
>>
>> Try:
>> noipv6rs
>> noipv6
>
> I tried both seperatily and together (even though the latter seems to includ
> the former), but ifconfig still shows ipv6 adresses. :-\
>
>> Have you looked at man dhcpcd.conf?
>
> Thats pretty much the first thing I did after your suggestion to edit that
> file. Its where I got that "ipv4only" thingy from (which doesn't work as
> I imagine it would).
>
>> Don't get too hung up on the raspbian/bullseye focus.
>> dhcpcd configuration is dhcpcd configuration no matter which distro you're
>> using.
>
> I've got to take your word for that, as I do not (yet) posess that
> knowledge - which is why I mentioned what my starting point is, so we would
> be on the same page. Thank you for mentioning it.
>
>> It seems there are 2 ways to totally disable ipv6
>
> And thanks for those. I think I found those myself too, but didn't
> actually
> read them as it /looked like/ dhcpcd.conf had the means to gouvern them (and
> assumed a similar problem as in regard to dhclient - looking at the wrong
> thing)
>
> But a bit of a bummer : I was assuming that I could disable it for one
> interface, but keep it enabled for another.
>
> Regards,
> Rudy Wieser
>
>
Unless you want to probe the dark slough of everyone else's hackery, I
strongly suggest that you give DHCP the old heave-ho on that interface
and go static.

DHCP is there to solve a problem you don't have.
Don't fight it. Or its myrmidons. Cut the Gordian knot and shoot it in
the head.

>

--
Canada is all right really, though not for the whole weekend.

"Saki"

On 26/04/2023 22:17, R.Wieser wrote:
> Ahem A Rivet's Shot,
>
>> What sort of ipv6 addresses ? If it is only link local ipv6
>> addresses (starting fe80::) then they don't come from DHCPCD but from IPv6
>> neighbour discovery and are probably quite hard to get rid of but they're
>> only valid on a LAN segment so I wouldn't worry about them too much.
>
>>> What sort of ipv6 addresses ? If it is only link local ipv6
>>> addresses (starting fe80::)
>
> it (eth1) is.
>
>> then they don't come from DHCPCD but from IPv6 neighbour discovery and are
>> probably quite hard to get rid
>
> So every of those "noipv6" and "ipv4only" things in (man) dhcpcd.config are
> fake ? They actually don't do squat ? That would perhaps have been a good
> april
> first joke, but not on any other day. :-(

It is not even sure where Raspian picks up its config files from. These
may belong to obsolete software 'left in place' because no one dared
touch it and the thing works now anyway.
>
>> of but they're only valid on a LAN segment so I wouldn't worry about them
>> too much.
>
> :-) All computers on my LAN (and probably yours too) have local ipv4
> adresses, but they can still connect to other computers all over the world.
>
> The thing is that that I have multiple computers on my lan, and I don't want
> to discover that one of them is using ipv6 - which I do not use and as such
> have very little knowledge of - as a weakpoint to gain access to others.
>
> Regards,
> Rudy Wieser
>
>
I shouldn't worry. IPv6 like so many other great ideas invented by
bright eyed bushy tailed ComputerScientists™, doesn't really work, and
probably never will.

The reality is that there are 32 bits of IPV4 address and 32 bits of
port addresses within that. More than enough

And 99% of all the worlds devices sit happily behind NAT routers.
Like most of TCP/IP, NAT is a kludge invented to MakeStuffWork, is ugly,
properly offends ComputerScientists™, but is robust enough to DoTheJob.

--
Those who want slavery should have the grace to name it by its proper
name. They must face the full meaning of that which they are advocating
or condoning; the full, exact, specific meaning of collectivism, of its
logical implications, of the principles upon which it is based, and of
the ultimate consequences to which these principles will lead. They must
face it, then decide whether this is what they want or not.

Ayn Rand.

On Thu, 27 Apr 2023 09:25:25 +0200
"R.Wieser" <address@is.invalid> wrote:

> Do you happen to know if its possible and if so how to configure ipv6 to
> /not/ to generate such a "link local address" and only expose an address
> if provided thru dhcp (so it functions the same way ipv4 works and its a
> per interface thing) ?

It is not DHCPv6 uses the link local addresses for communication.
They're rather fundamental.

> Sort of. /Some/ "IPv4 private addresses" may go one way, /others/ may go
> the other way. Which ones is under control of and has to be configured
> per router.

Quite it's by convention and if the router misbehaves the 'private'
addresses leak. Whereas the link local addresses are protocol level and
their behaviour is built into the IPv6 stack.

> > I'm not sure it's possible to NAT IPv6 link local addresses, you'd
> > certainly have to work at it,
>
> Do you know What would be the difference between ipv4 and ipv6 that would
> make it especially hard to do for the latter ?

The Ipv6 NAT protocol definition :)

> > by default there's no kind of NAT used for IPv6 the addresses are
> > either link local or public.
>
> Thats just because there are way more ipv6 IPs available than we
> currently can use, and NAT-ing hem would (look to) be a bit silly - an
> exercise in futility.

I rather think there are more than we will ever be able to use. If
I turn on IPv6 from my ISP I get a /56 block all to myself, or Hurricane
Electric will give me a /48 and a /64 over a free tunnel. By contrast I had
to pay for the use of a *single* static IPv4 address.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

On Thu, 27 Apr 2023 09:40:40 +0100, The Natural Philosopher wrote:

> I have concluded that like so much software, Mint/Ubuntu/Debian is being
> overwhelmed by the dreaded weed Creeping Featurism and and has been
> debugged only insofar as to work for 'normal' situations, and underneath
> is a BFM. A Bloody Fucking Mess, that like postscript and X windows has
> been stabilised by the general principle of 'buggering around till it
> sorta works'.
>
Its also worth remembering that your LAN's firewall router may well have a
DHCP router buried in its innards and if this device suffers from bit rot
in the EPROM that holds its firmware and configuration parameters, then
you can get some unpleasant network problems, particularly a problem for
those of us still limited to ADSL connections;

**cough** D-Link DSL-320B **cough**

The only source of replacement ADSL routers now appears to be eBay:

--

Martin | martin at
Gregorie | gregorie dot org

On 27/04/2023 10:36, Martin Gregorie wrote:
> On Thu, 27 Apr 2023 09:40:40 +0100, The Natural Philosopher wrote:
>
>> I have concluded that like so much software, Mint/Ubuntu/Debian is being
>> overwhelmed by the dreaded weed Creeping Featurism and and has been
>> debugged only insofar as to work for 'normal' situations, and underneath
>> is a BFM. A Bloody Fucking Mess, that like postscript and X windows has
>> been stabilised by the general principle of 'buggering around till it
>> sorta works'.
>>
> Its also worth remembering that your LAN's firewall router may well have a
> DHCP router buried in its innards and if this device suffers from bit rot
> in the EPROM that holds its firmware and configuration parameters, then
> you can get some unpleasant network problems, particularly a problem for
> those of us still limited to ADSL connections;
>
> **cough** D-Link DSL-320B **cough**
>
> The only source of replacement ADSL routers now appears to be eBay:
>
>
Really?

Yeah, My well hated router was not D-link. That did well till lightning
popped its front end, but Netgear. I have one of those serving as a wifi
access point, it needs rebooting now and again. It also got unreliable
after a heavy storm

Consumer routers are mostly utter crap. I have a Draytek now, and it all
actually works.

Its got ADSL but Ive migrated to fibre, and id does ethernet WAN as well
(like cable)

--
Gun Control: The law that ensures that only criminals have guns.

Ahem,

> It is not DHCPv6 uses the link local addresses for
> communication.

I'm still not grasping the distinction between an ipv6 and ipv4 "local
address" I'm afraid.

> They're rather fundamental.

I've just disabled ipv6 on my RPi and have not noticed anything failing.
IOW, they can't be /that/ fundamental.

If you mean they are fundamental in regard to communication between
computers on the same lan segment, than thats exactly what I want to limit -
especially as I have no idea what services have ipv6 ports open.

> Whereas the link local addresses are protocol level and
> their behaviour is built into the IPv6 stack

I don't quite get that I'm afraid : If data send and received using such a
link local address can be read by software connecting to the ipv6 stack,
what than stops a router to do with as it pleases ?

Or, said otherwise : if the ipv6 stack somehow internally blocks data send
using such a link local address how would a router - or even a standard
'puter - be able to use that local link address to begin with ?

>> Thats just because there are way more ipv6 IPs available than we
>> currently can use, and NAT-ing hem would (look to) be a bit silly - an
>> exercise in futility.
>
> I rather think there are more than we will ever be able to use.

:-) Thats what I tried to convey.

Regards,
Rudy Wieser

The Natural Philosopher wrote:

> The reality is that there are 32 bits of IPV4 address and 32 bits of
> port addresses within that.

16 bits of ports ...

On a sunny day (Thu, 27 Apr 2023 09:40:40 +0100) it happened The Natural
Philosopher <tnp@invalid.invalid> wrote in <u2dce8$1r7v6$1@dont-email.me>:

>I conclude that in later versions of Mint desktop systems neither
>dhclient nor dhcpd are used.
>
>I have found the layer upon layer of obsolete and obsolescent networking
>files to be a total pain to deal with.
>
>And indeed even though my server is set to static IP address via
>network manager it also has a ghost IP address assigned by DHCP. This
>responds to pings and shows up on the router dhcp tables, but is
>otherwise completely unused for anything
>
>I have concluded that like so much software, Mint/Ubuntu/Debian is being
>overwhelmed by the dreaded weed Creeping Featurism and and has been
>debugged only insofar as to work for 'normal' situations, and underneath
>is a BFM. A Bloody Fucking Mess, that like postscript and X windows has
>been stabilised by the general principle of 'buggering around till it
>sorta works'.

I agree.
Thing changed by tinkerers who did not even understand the original intention of the code.

In my other rapi4 4 GB I have killed dhc.. at startup,
and then run my own script setting the interfaces on the LAN.
All fixed IP addresses
Uptime 54 days now it says... no problems.

On this one I am posting from, a Pi4 8 GB, dhWCd or whatever still runs.
raspberrypi: ~ # uname -a
Linux raspberrypi 5.15.32-v7l+ #1538 SMP Thu Mar 31 19:39:41 BST 2022 armv7l GNU/Linux

But I still run my own config scripts after it started,
this one has a 4G USB stick plugged in and also functions as route for or example my laptop.

That whole RatHead dbus shit should be outlawed.
So stupid, to start Apache webserver was (Slackware):
apachectl start

now it is, on my raspi 4 8 GB:
service apache2 start

WHY?

And the same for user interfaces, does google gets its programmers from <insert low IQ group here>?
Ever more memory needed, even for simple text things..., annoying interfaces...
People need gigabytes to do the simplest things, were I can often do the same in a few kB (yes KB)...

Now I know many 'merricans cannot read or write, so mouse clicking at a mouse picture expects them so catch a mouse... ?
But really, command line is faster here, especially when running zsh as shell.

Script to start net connection and config the Pi as router:
/usr/local/sbin/start_4g_router

#!/usr//bin/bash
iptables -F
route add -net 192.168.0.0/16 dev eth0
echo 1 >/proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING ! -d 192.168.0.0/16 -o eth1 -j SNAT --to-source 192.168.8.100
sleep 1
ifconfig eth0 down
sleep 1
ifconfig eth0 192.168.178.1 up
sleep 1
vnstat -i eth1 -s
# default is set to 192.168.8.1, that blocks rt.com, this uses 8.8.8.8 an 8.8.4.4
cp /etc/resolv.conf.GOOGLE /etc/resolv.conf
sleep 1

Script to turn internet connection on or off:
/usr/local/sbin/set_4g

#!/usr/bin/bash
if [ "$1" == "off" ]
then
ifconfig eth1 down
elif [ "$1" == "on" ]
then
ifconfig eth1 up
cp /etc/resolv.conf.GOOGLE /etc/resolv.conf
else
echo "Usage: set_4g on | off"
fi

Damn it, moon landing used only kilobytes, now they crash (Japan) with gigabytes on board..
https://panteltje.nl/panteltje/quadcopter/index.html
can drop things too:
https://panteltje.nl/panteltje/quadcopter/drop.html

Keep It Simple!!
Moon landing game I played in the seventies on what was it, a Commodore Pet?
https://en.m.wikipedia.org/wiki/Commodore_PET
When the moon landings happened I was working in the TV head control room in my country to pass it on to the people.
Lots of tubes there in those days, hundreds... few transistors ... Had to fix it too if the system (and it did on a regular basis) failed.
But always was 'online'.
Kids, cellphones., wait for the next high altitude nuke, or big solar storm
NOTHING will work.
OK :-)
2024 I think.

Society over the hill, climate idiots, brainwashed people that believe the CO2 snake oil sales pitch.
Climate change is caused by changes in the earth orbit and sun:
http://old.world-mysteries.com/alignments/mpl_al3b.htm

Society is 'over the hill'
like in medieval times witch-hunts now it is hunts for CO2 emitters.
Mass hysteria
We NEED a global war to get back to normal
Radiation is not so bad, still alive after inhaling some Chernobyl fallout here many years ago.
The airco filters where I worked had to be replaced because those were 'hot'.
Wars are part of evolution,...
And US REALLY needs those to sell more weapons, so they keep asking ..
Better save your raspi in a metal box,
although I had some transistors in a metal box and those died anyways next to my 250 W or so transmitter
So your mileage may vary

Wars, one ant heap against the other, the best one wins, evolution.

Wonder how long it will take before kids can buy a 'make your own dino' kit at Walmart or on ebay from China ..
And then legislation forbidding it after some school playground got messed up by those dinos.
Killing life, followed by creating life as a hobby, all sort of new interesting species.

Not even mentioning AI getting to work and design it for you, THAT is easy.
Ooops text file, you will need to learn to write and read.
Oh no, wait, voice input...
AI make me a wild wild dino.

?
/

On 27/04/2023 11:56, Andy Burns wrote:
> The Natural Philosopher wrote:
>
>> The reality is that there are 32 bits of IPV4 address and 32 bits of
>> port addresses within that.
>
> 16 bits of ports  ...
>
>
Ah. Brain fade. Yes

--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal

On 27/04/2023 08:35, R.Wieser wrote:
> Chris,
>
>> a) if using sysctl: put a file in /etc/sysctl.d/ containing
>> net.ipv6.conf.all.disable_ipv6 = 1
>> net.ipv6.conf.default.disable_ipv6 = 1
>> net.ipv6.conf.lo.disable_ipv6 = 1
>
> I've applied all three, and after rebooting looking at ifconfig I do not see
> any ipv6 any more. Thank you.
>
> One question though : The latter two entries seem to be subsets of the first
> one. Is there something I'm missing or is this just a case of wearing a
> belt /and/ suspenders ?
>
> Regards,
> Rudy Wieser
>
>

Agreed, they do seem to be subsets. I don't know why.
But further investigation shows that commenting out (or removing) the
above 3 lines and putting just
net.ipv6.conf.eth1.disable_ipv6 = 1
will disable ipv6 on only that interface (eth1)
Note that you must have the interface name correct for it to work.

--
Chris Elvidge
England

On 27/04/2023 09:50, The Natural Philosopher wrote:
> It is not even sure where Raspian picks up its config files from. These
> may belong to obsolete software 'left in place' because no one dared
> touch it and the thing works now anyway.

Raspbian uses systemd for configuration.

As stock, it will use whatever service is specified in
/usr/lib/systemd/system/ (previous versions may use /lib/systemd/system/)

On mine it is dhcpcd.service with ExecStart=/usr/sbin/dhcpcd -b -q
To me, that means configuration is done in /etc/dhcpcd.conf

Another possibility is NetworkManager.service, configuration in
/etc/NetworkManager/*

One I've never seen is dhclient.service which would have configuration
in /etc/dhclient/dhclient.conf

--
Chris Elvidge
England

On Thu, 27 Apr 2023 10:47:54 +0100, The Natural Philosopher wrote:

> Really?
>
Yes, really. The DSL320B I've used for years currently has several
problems:

- its screwing with the fourth term of the IP address,which causes pinging
other hosts on my LAN to fail - this seems to be corrupting the 4th term
of a fixed IP address

- my DSL320B can currently connect to the outside world from either of the
two hosts on my LAN, but neither host can talk to the other one.
AFAIK there's no problem with my CAT5/6 switch

- the DSL320B should be configurable via http or telnet, but neither
Firefox nor Lynx shows any ability to access the DSL320B via an http
connection. If I point telnet at it, it accepts the default user name,
'admin', but doesn't accept the password, which also defaults to 'admin'.

- I got a replacement off eBay, because I couldn't find a retailer with
any in stock and its even worse. It won't even accept the default user
name. and can't be pinged.

- The DSL320B manual says you can reset a DSL320B by poking a 'biro'
into a 'reset' hole, but this is a lie: the hole is both too small and
too deeply inset for any biro I've seen to work.

However it should be resettable if you push a toothpick, some 1mm alloy
tube or a shaved down matchstick into the small (1.5mm) 'reset' hole
until you hear the switch click while holding the power switch down and
keeping it pressed 10-15 seconds, but this failed to reset either of the
DSL320Bs.

> Consumer routers are mostly utter crap. I have a Draytek now, and it all
> actually works.
>
> Its got ADSL but Ive migrated to fibre, and id does ethernet WAN as well
> (like cable)
>
My problem is that there currently is no fibre available where I live: its
ADSL or nothing at present as I'm not keen on WiFi.

I'm currently on the Zen waiting list until fibre connectivity gets
installed (I'm not holding my breath for this) but am about to see if they
Zen can take over my current ADSL link anyway, by installing a Fritz box,
which is what they apparently use as the fibre terminator, but for use as
an ADSL terminator in the meantime.

--

Martin | martin at
Gregorie | gregorie dot org

On Thu, 27 Apr 2023 12:02:52 +0200
"R.Wieser" <address@is.invalid> wrote:

> Ahem,
>
> > It is not DHCPv6 uses the link local addresses for
> > communication.
>
> I'm still not grasping the distinction between an ipv6 and ipv4 "local
> address" I'm afraid.

IPv6 link local addresses are local to the LAN segment (they
cannot be used for forwarding enforced by the stack), generated
automatically on the host with a duplicate address detection phase and used
for DHCPv6 communication to provide public addresses, router information
etc.

IPv4 private addresses are local to the LAN, they can and are used
for forwarding across routers on a LAN but should not be routed across the
public internet. It is only firewall configuration in routers that prevents
this.

> > They're rather fundamental.
>
> I've just disabled ipv6 on my RPi and have not noticed anything failing.
> IOW, they can't be /that/ fundamental.

fundamental to IPv6, it won't work without them.

> > Whereas the link local addresses are protocol level and
> > their behaviour is built into the IPv6 stack
>
> I don't quite get that I'm afraid : If data send and received using such
> a link local address can be read by software connecting to the ipv6
> stack, what than stops a router to do with as it pleases ?

The definition of the IPv6 protocol. Yes you could hack the
protocol stack to do anything you like but as long as you have a compliant
IPv6 stack then the link local address will never be used as a source
address unless the target is another link local address and packets with
link local addresses (either target or source) will never be forwarded they
have to go direct or not at all.

> Or, said otherwise : if the ipv6 stack somehow internally blocks data
> send using such a link local address how would a router - or even a

It doesn't block sending it blocks forwarding - for a packet to
leave a machine with link local addresses it has to originate on that
machine, if it arrives for forwarding it will be dropped. IOW the only link
local target address a host accepts is the one on the interface the packet
arrived at.

> standard 'puter - be able to use that local link address to begin with ?

The link local address can be used between hosts on the same LAN
segment so for example it is very common for the link local address of a
router to be used as the default route by every host using that router.
This address will remain unchanged (and advertised via DHCPv6) no matter
what changes are made to the routed networks.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/

Chris,

> But further investigation shows that commenting out (or removing)
> the above 3 lines and putting just
> net.ipv6.conf.eth1.disable_ipv6 = 1
> will disable ipv6 on only that interface (eth1)

Now you say that I remember having seen that been mentioned before. Didn't
focus on it though, as I thought dhcpcd.conf would rule those settings. :-\

Hmmmm... I wonder if I can use a

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.eth1.disable_ipv6 = 0

sequence to disable all /but for/ a specific interface ...

<testing>

Yup, seems to work. Nice.

> Note that you must have the interface name correct for it to work.

Are you sure about that ? I cannot just make up a word, put it there have
the setting applied to the interface I was thinking of ? Bummer ... :-)

Regards,
Rudy Wieser

Ahem,

>> I've just disabled ipv6 on my RPi and have not noticed anything
>> failing. IOW, they can't be /that/ fundamental.
>
> fundamental to IPv6, it won't work without them.

My brain balks about something thats "fundamental to IPv6", but is not an
/internal/ IP (like 127.x.x.x) is. One of my pet peeves with Windows is
that certain open ports facing the LAN cannot be closed (no way to do it)
and terminating the service that opens them cannot be done as the service is
also used for the internal working of the OS (using a 127.x.x.x IP).

> but as long as you have a compliant IPv6 stack then the link local
> address will never be used as a source address unless the target is
> another link local address

And thats an explanation I can understand : both the source and target must
be "link local addresses" to be able to make it thru the ipv6 stack. Obvious
when you are aware of it (as with so many things). Thank you.

>> standard 'puter - be able to use that local link address to begin
>> with ?
>
> The link local address can be used between hosts on the same LAN
> segment

:) That was not quite what I ment.

I was trying to wrap my head around how an "link local address" datapacket
could come outof the ipv6 stack in a 'puter, but not outof the same in a
router. Your "source and target must be of the same kind" explained it.

Regards,
Rudy Wieser

On 27/04/2023 13:07, Martin Gregorie wrote:
> My problem is that there currently is no fibre available where I live: its
> ADSL or nothing at present as I'm not keen on WiFi.

I have a pretty good Cisco (Linksys rebadged) SOHO ADSL router
Its even got PSTN ports for voip.

Needs a wall wart as I pinched that for the Netgear.

Runs warm in use, but never fails.
If you are in the UK I'll post it

--
“The ultimate result of shielding men from the effects of folly is to
fill the world with fools.”

Herbert Spencer

On 27/04/2023 15:04, The Natural Philosopher wrote:
> On 27/04/2023 13:07, Martin Gregorie wrote:
>> My problem is that there currently is no fibre available where I live:
>> its
>> ADSL or nothing at present as I'm not keen on WiFi.
>
> I have a pretty good Cisco (Linksys rebadged) SOHO ADSL router
> Its even got PSTN ports for voip.
>
> Needs a wall wart as I pinched that for the Netgear.
>
> Runs warm in use, but never fails.
> If you are in the UK I'll post it
>
>
>
Oh. I can still buy ADSL routers without WiFi in the UK

https://www.broadbandbuyer.com/products/25841-draytek-v2832-k/

Very very good router, that.

--
“But what a weak barrier is truth when it stands in the way of an
hypothesis!”

Mary Wollstonecraft

On Thu, 27 Apr 2023 15:24:50 +0200
"R.Wieser" <address@is.invalid> wrote:

> My brain balks about something thats "fundamental to IPv6", but is not an
> /internal/ IP (like 127.x.x.x) is.

It sort of is internal - to the LAN not the machine, rather like
MAC addresses, the main use is to enable unicast addressing to be used for
almost everything and minimise the use of broadcast addressing. It's all
about scalability really - making it easy to manage a LAN with tens of
thousands of hosts (horrible thought!).

Cellphone data plan connections use IPv6 and need it AFAICT, IPv4
NAT and DHCP would be a nightmare in that environment.

--
Steve O'Hara-Smith
Odds and Ends at http://www.sohara.org/