Why does my computer keep disappearing from the local network?

In article , Eric Stevens
wrote:

Corsair IPV4 169.254.1.22

it failed to get an ip address via dhcp.

Dell IPV4 192.168.1.1

that should be the ip address of your router, not the dell.

Networking is something I know little about.

i'm well aware of that

To avoid confusion here
is the current network information from Corsair
https://www.dropbox.com/s/fgm16wxgxk...twork.JPG?dl=0

that is not current, since it shows that the dhcp lease expired in
november, 2018.

nevertheless, your router is 192.168.1.1 (not the dell), and the
corsair's ip address is 192.168.1.8

and from Dell
https://www.dropbox.com/s/93p5nuet1o...twork.JPG?dl=0

that one is current, with the dhcp lease expiring tomorrow.

its ip address is 192.168.1.16

I notice that the IP4 address has changed for both Dell and Corsair
since earlier in the day.

it should not be changing.

your dhcp lease time is 24 hours, however, it should get the same ip
address when it renews.

I snipped both screen shots and left them on the respective desk tops.
Corsair had no trouble getting the snapshot from Dell. Its working the
other way that things seem to be blind.

that is likely something about windows, not the network.

On 16/07/2019 06:10, Eric Stevens wrote:
I notice that the IP4 address has changed for both Dell and Corsair
since earlier in the day.

Best thing is to flush the dns from both/all machines by typing:

ipconfig /flushdns
Do this couple of times just in case something is missed!!

The above command goes in the cmd prompt as Administrator. Right-Click
on the Windows orb/start button and choose Command Prompt (Admin) to get
a prompt. You'll need to provide an admin password.

After that type:

ipconfig /displaydns

This will display DNS servers that CAN'T be flushed. Some will populate
from your hosts file if it's not empty but some are Microsoft's reserved
and some are from big corporations that pays Microsoft to protect their
DNS records from users!!.

From your recent postings I surmise that you have two routers - one is
a broadband modem and other is a switch so I am now confused because all
modems can work as a router so not sure why you need a switch. I'm
assuming you don't have more than 4 machines in the house that needs
ethernet connection.

By the way IP addresses can change because that is the purpose of
allocating them dynamically but in practice, Windows keep a cache of
addresses that are reused unless there is a conflict with some other
machines. By flushing them from machines, you are starting from scratch
and both/all machines will recreate a new cache when they can connect to
your router(s).

Printers are always on Static addresses because you don't want their
addresses to keep changing. All machines connect to that one printer so
the address needs to be static. This is a settings in the printer but
this not your problem for now so ignore this comment.

New Zealand were just unlucky to lose on silly rules but hey that's
cricket where rules are made to be applied!!.





--
With over 999 million devices now running Windows 10, customer
satisfaction is higher than any previous version of windows.

In article , ? Good Guy ?
wrote:

On 16/07/2019 06:10, Eric Stevens wrote:
I notice that the IP4 address has changed for both Dell and Corsair
since earlier in the day.



From your recent postings I surmise that you have two routers - one is
a broadband modem and other is a switch so I am now confused because all
modems can work as a router

many do, but not all, and their router functionality is usually limited
and/or locked down.

so not sure why you need a switch.

because he has more hardwired devices than available ports on the
router, or he wants to run one cable to another room which has multiple
devices, rather than run multiple cables to each device.

I'm
assuming you don't have more than 4 machines in the house that needs
ethernet connection.

bad assumption.

By the way IP addresses can change because that is the purpose of
allocating them dynamically but in practice, Windows keep a cache of
addresses that are reused unless there is a conflict with some other
machines. By flushing them from machines, you are starting from scratch
and both/all machines will recreate a new cache when they can connect to
your router(s).

nope. the dhcp server decides what ip address to assign, and normally
it's the same ip address when the dhcp lease is renewed.

Printers are always on Static addresses because you don't want their
addresses to keep changing. All machines connect to that one printer so
the address needs to be static. This is a settings in the printer but
this not your problem for now so ignore this comment.

best to ignore it, since it's wrong.

there is very rarely a need for static ip addresses. a much better
choice is dhcp reservation, better yet is use the hostname and let dns
worry about it and ideally, use zeroconf/bonjour/avahi.

nospam wrote:
In article , ? Good Guy ?
wrote:

so not sure why you need a switch.

because he has more hardwired devices than available ports on the
router, or he wants to run one cable to another room which has multiple
devices, rather than run multiple cables to each device.

My router has 100BT on the LAN side.

I use a four port GbE box downstream of the
router, to allow LAN to LAN transfer at GbE
speed.

That's why you use a separate switch.

My broadband service is too slow for 100BT to
be an issue. The router only has 18Mbit/sec
WAN to LAN capability and I use 15Mbit/sec of
that. The router is basically (almost) to the wall.
It's pretty gutless. But, there's a reason
for doing it this way. It's not "cheapness",
it's the function set I get from the whole mess.

My network has no IPV6 running on it, and only
Teredo tunneling could get out.

Paul

In article , Paul
wrote:

so not sure why you need a switch.

because he has more hardwired devices than available ports on the
router, or he wants to run one cable to another room which has multiple
devices, rather than run multiple cables to each device.

My router has 100BT on the LAN side.

that's another reason to use a switch.

better yet, replace the router.

I use a four port GbE box downstream of the
router, to allow LAN to LAN transfer at GbE
speed.

only 4?

i just bought a 48 port switch. that should be enough for a while...

That's why you use a separate switch.

an old 100bt router is just one reason.

My broadband service is too slow for 100BT to
be an issue. The router only has 18Mbit/sec
WAN to LAN capability and I use 15Mbit/sec of
that. The router is basically (almost) to the wall.
It's pretty gutless. But, there's a reason
for doing it this way. It's not "cheapness",
it's the function set I get from the whole mess.

that's really slow.

On 2019-07-13 23:19, Eric Stevens wrote:
I have two computers, 'Corsair' and 'Dell' on an ethernet network
sharing two printers modem. Both computers are running Windows 10 Pro.
Both printers have Internet connections. Corsai has always been a
pain in the plectrum and one of its habits is to keep disappearing
from the network.

Right now, when I check the network, there is no sign of it but some
times it shows up as a media device. This is the situation when I
check from either Corsair or Dell. I can easily bring it out of
hiding. All I have to do is reset the network from Corsair. But one or
two days later it has gone again.

I've now spent nearly two years struggling with this machine and as
far as I can tell both Corsair and Dell use the same settings. But
Dell behaves itself and Corsair continues to be a pig.

I have no idea of what setting is changing and no idea of where I
should be looking. Has anyone got any suggestions about what I should
be looking for?


What we need is to verify the following:

the IPv4 address and subnet mask of the router, both computers, and any
other devices such as printers.

the IPv4 DNS address (should be the same as the IPv4 router address, or
should be a standard Internet-accessible IPv4 DNS)

the IPv4 DHCP address (should be the same as the IPv4 router address
unless you have a dedicated DHCP server, which most people at home don't.)

the lease information for both computers

the IPv4 default gateway for both computers (should be the same as the
IPv4 router address)

Example: my computer is currently configured as follows:

IPv4 address: 192.168.100.201
Subnet mask: 255.255.255.0
Default gateway: 192.168.100.1
DHCP server: 192.168.100.1
DNS Servers: 1.1.1.1, 1.0.0.1
Lease obtained: 16 July 2019 17:57:45
Lease expires: 17 July 2019 17:57:46

192.168.x.y where 'x' is 0 to 255 and 'y' is 1 to 254 is a private Class
C network. The subnet mask must be 255.255.255.0 to get a Class C;
anything else is not a Class C. You _must_ have the first three octets
be identical for all items. Anything which has even one of the first
three different is NOT on the same network as the others. Anything which
does not have the subnet mask being the same as the others is also not
on the same network, even if the first three octets are the same. (Note:
this is for a Class C. The rules are slightly different for Class A,
Class B, or Classless networks; the subnet masks still have to be the
same, the octet settings are different. You don't care about that, you
have a Class C.)

I'm using Cloudflare's DNS. I'm using DHCP, so I have a 'lease' on the
IPv4 address 192.168.100.201. This machine is part of a Class C network
whose network octets are 192.168.100. The DHCP server will check my
machine using its hardware (MAC) address (you don't care) at the halfway
and at the end of the lease; if the machine is still connected, the
lease is renewed for another day. (DHCP servers may be configured to
have leases measured in minutes, hours, or days, depending on the
administrator's wishes.) If the machine is not connected, it loses the
lease. If the machine connects later, the DHCP server may reinstate the
lease, if no other machine has grabbed that IP address in the meantime,
as the DHCP server knows the machine's MAC address. (The DHCP server
cares about the MAC address. You don't, unless you're setting up a DHCP
IP reservation, and even then you care only long enough to set up the
reservation and stop caring immediately thereafter.)

My machine is configured with IPv6 as well as Ipv4, but it's irrelevant
to this discussion.

On 2019-07-15 23:39, Eric Stevens wrote:
On Sun, 14 Jul 2019 14:14:00 +0200, "Carlos E.R."
wrote:

On 14/07/2019 05.19, Eric Stevens wrote:
I have two computers, 'Corsair' and 'Dell' on an ethernet network
sharing two printers modem. Both computers are running Windows 10 Pro.
Both printers have Internet connections. Corsai has always been a
pain in the plectrum and one of its habits is to keep disappearing
from the network.

Right now, when I check the network, there is no sign of it but some
times it shows up as a media device. This is the situation when I
check from either Corsair or Dell. I can easily bring it out of
hiding. All I have to do is reset the network from Corsair. But one or
two days later it has gone again.

I've now spent nearly two years struggling with this machine and as
far as I can tell both Corsair and Dell use the same settings. But
Dell behaves itself and Corsair continues to be a pig.

I have no idea of what setting is changing and no idea of where I
should be looking. Has anyone got any suggestions about what I should
be looking for?


You should find out first if the machine is really disconnected from the
network, or is its name not showing. For example, does it respond to
pings - by IP address, not name?

Corsair IPV4 169.254.1.22

That's an APIPA, an Automatic Private IP Address, address. It means that
the Corsair can't see the DHCP server.

Dell IPV4 192.168.1.1

The Dell is on a Class C private network with the network octets set to
192.168.1. This is possibly the most common private Class C network in
the world, most ISP modem/routers are set to use something similar.
Warning: the most common gateway/DHCP/router addresses are 192.168.1.1,
so your Dell is sitting on a possible router address. You might want to
change that. ISPs such as Comcast usually is 192.168.1.1; AT&T usually
uses 192.168.1.254, because, well, they're AT&T. The default settings
issued by the ISP can be changed using the modem/router settings page. I
don't recommend doing that unless you know what you're doing and a have
reason to do it.


Corsair ping Dell 32bytes 1ms TTL=64

Dell ping Corsair Request timed out
4 packest sent 0 received Lost 4

Corsair ping Corsair Destination host unreachable
4 packest sent 0 received Lost 4

The Dell and the Corsair are not on the same network. They can't see
each other unless there's a router involved. If the Corsair could see
the router, it would have an address on the 192.168.1 network and the
Dell could ping it.


Yet Corsair happily prints to (normally) either of the printers on the
network. It still prints to the Oki (see below).

I suspect that the printers are using some variety of zeroconf, and are
identified by name, not IP.



Corsair Dell Oki Epson
| | Print Print|
| | | |
[=============Switch================]
|
[Modem]
|
Internet

If you try open a resource on it, does it work? Or if one was opened
before (say, shared folder), does it keep working?

At the moment Corsair can see Dell and its shared files and folders.
It can see the Oki printer, but not the Epson (It seems Epson
currently has the wrong driver. I must fix that). It also sees the
Google Dongle in the living room and somebody's cell phone.

The problem is different one way or the other.

On 2019-07-16 01:34, Eric Stevens wrote:
I've tried entering the Router to see how it is presently configure
but it is not presently responding to my attempts get in with
192.168.20.1. I will reset things and try again later.

That's because 192.168.20.1 is not on the same network as the router.
The router should be on 192.168.1.1.

On 2019-07-16 00:20, nospam wrote:
In article , Eric Stevens
wrote:

Corsair IPV4 169.254.1.22

it failed to get an ip address via dhcp.

exactly.


Dell IPV4 192.168.1.1

that should be the ip address of your router, not the dell.


I thought that that was probably the router's address.

"Eric Stevens" wrote in message
...

I have two computers, 'Corsair' and 'Dell' on an ethernet network
sharing two printers modem. Both computers are running Windows 10 Pro.
Both printers have Internet connections. Corsai has always been a
pain in the plectrum and one of its habits is to keep disappearing
from the network.

It may help to have some commonality across both devices.

Windows 10 (both devices)
- Ensure you have a common Windows logon username/password profile on each
device(same name, same password)
- Do not configure either device to auto logon
- Ensure sharing is configured(since you can connect, it most likely it is)
with folders(shared on each device)
- Ensure each device is configured for the same work group
- Different Computer name on each device(if you've configured both with the
same name, change one)
= Remember the ComputerName for each device(you'll need it later)
e.g. One Computername Corsair, the other Computername Dell. For
networking purposes when a need to enter the computer name it would be
entered as \\Corsair and \\Dell (remember this, it might come in handy)

Services(set all below to automatic, IWin10 may reset one of more of the
first two items to Auto(Triggered), if so reset it to Automatic. All these
services started
- Function Discovery Provider Host
- Function Discovery Resource Publication
- SSDP Discovery
- UnPnP Device Host

Windows Features and Programs
- SMB 1.0/CIFS File Sharing Support
Uncheck(if present) SMB 1.0/CIFS Automatic Removal
Check SMB 1.0/CIFS Client and SMB 1.0/CIFS Server
= The first(auto removal) is design intent, the latter two not
enabled -all due to security risk.
If willing to ignore the risk, since these features may need to be enabled
disable and enable as noted

Windows Credentials
On each device create a Windows Credential for the each ComputerName using
the common username/password(suggesting at the beginning of this post, 1st
item under 'Window 10(both devices)'
e.g. If the common Windows Logon is Cameo(username) and password then create
a credential for that \\ComputerName Enter the \\Computername in the
Network field then enter the username Cameo and password in the dialog
creation box. Repeat this process on both machines until you have 2 Windows
Credentials created on each device(one for each \\ComputerName and both with
same username/pw)

Win10 can still be persnickety about connecting due to device other device
not on, sleeping, hibernating, wifi power management turning off wifi.

For the most part, the devices will be accessible on each device and appear
in File Explorer/Network...if not shown in File Explorer under Network, just
enter the \\Computername in the File Explorer address field to access and
populate the shared folders in File Explorer's Navigation and Display pane.


-- --
....w¡ñ§±¤ñ
msft mvp 2007-2019

On Tue, 16 Jul 2019 08:42:32 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

Corsair IPV4 169.254.1.22

it failed to get an ip address via dhcp.

Dell IPV4 192.168.1.1

that should be the ip address of your router, not the dell.

Networking is something I know little about.

i'm well aware of that

To avoid confusion here
is the current network information from Corsair
https://www.dropbox.com/s/fgm16wxgxk...twork.JPG?dl=0

that is not current, since it shows that the dhcp lease expired in
november, 2018.

That's daft! I never saw that.

nevertheless, your router is 192.168.1.1 (not the dell), and the
corsair's ip address is 192.168.1.8

and from Dell
https://www.dropbox.com/s/93p5nuet1o...twork.JPG?dl=0

that one is current, with the dhcp lease expiring tomorrow.

its ip address is 192.168.1.16

I notice that the IP4 address has changed for both Dell and Corsair
since earlier in the day.

it should not be changing.

your dhcp lease time is 24 hours, however, it should get the same ip
address when it renews.

I snipped both screen shots and left them on the respective desk tops.
Corsair had no trouble getting the snapshot from Dell. Its working the
other way that things seem to be blind.

that is likely something about windows, not the network.

That's what I have always assumed.

On Tue, 16 Jul 2019 14:02:00 -0400, nospam
wrote:

In article , ? Good Guy ?
wrote:

On 16/07/2019 06:10, Eric Stevens wrote:
I notice that the IP4 address has changed for both Dell and Corsair
since earlier in the day.



From your recent postings I surmise that you have two routers - one is
a broadband modem and other is a switch so I am now confused because all
modems can work as a router

many do, but not all, and their router functionality is usually limited
and/or locked down.

so not sure why you need a switch.

because he has more hardwired devices than available ports on the
router, or he wants to run one cable to another room which has multiple
devices, rather than run multiple cables to each device.

That's the explanation. Two computers and two printers upstairs.
Router/modem at the fibre termination downstairs.

I'm
assuming you don't have more than 4 machines in the house that needs
ethernet connection.

bad assumption.

By the way IP addresses can change because that is the purpose of
allocating them dynamically but in practice, Windows keep a cache of
addresses that are reused unless there is a conflict with some other
machines. By flushing them from machines, you are starting from scratch
and both/all machines will recreate a new cache when they can connect to
your router(s).

nope. the dhcp server decides what ip address to assign, and normally
it's the same ip address when the dhcp lease is renewed.

Printers are always on Static addresses because you don't want their
addresses to keep changing. All machines connect to that one printer so
the address needs to be static. This is a settings in the printer but
this not your problem for now so ignore this comment.

best to ignore it, since it's wrong.

there is very rarely a need for static ip addresses. a much better
choice is dhcp reservation, better yet is use the hostname and let dns
worry about it and ideally, use zeroconf/bonjour/avahi.

On Tue, 16 Jul 2019 19:56:08 -0400, "...winston"
wrote:

"Eric Stevens" wrote in message
.. .

I have two computers, 'Corsair' and 'Dell' on an ethernet network
sharing two printers modem. Both computers are running Windows 10 Pro.
Both printers have Internet connections. Corsai has always been a
pain in the plectrum and one of its habits is to keep disappearing
from the network.

It may help to have some commonality across both devices.

Windows 10 (both devices)

Window 10 Pro 1903, both devices.

- Ensure you have a common Windows logon username/password profile on each
device(same name, same password)

I believe I do but my the next question in my series if I ever get
there is why Corsair has from time to time rejected any attempt of
mine to access shared folders and tells me I am not authorised.
Meantime Dell is happy to accept me. But lets not get into that for
the timebeing.

- Do not configure either device to auto logon

Nope.

- Ensure sharing is configured(since you can connect, it most likely it is)
with folders(shared on each device)

Already done.

- Ensure each device is configured for the same work group

There is a problem in that area. Smetimes they are the same. Sometimes
they are not. At the moment they are not.

- Different Computer name on each device(if you've configured both with the
same name, change one)

Corsair and Dell, as per this thread.

= Remember the ComputerName for each device(you'll need it later)
e.g. One Computername Corsair, the other Computername Dell. For
networking purposes when a need to enter the computer name it would be
entered as \\Corsair and \\Dell (remember this, it might come in handy)

Done that previously.

Services(set all below to automatic, IWin10 may reset one of more of the
first two items to Auto(Triggered), if so reset it to Automatic. All these
services started

Comments below elate to Corsair.

- Function Discovery Provider Host
Running, manual

- Function Discovery Resource Publication
Running, Manual(triggered)

- SSDP Discovery
Not running, manual

- UnPnP Device Host
Not running, Manual

Windows Features and Programs
- SMB 1.0/CIFS File Sharing Support
Uncheck(if present) SMB 1.0/CIFS Automatic Removal
Check SMB 1.0/CIFS Client and SMB 1.0/CIFS Server
= The first(auto removal) is design intent, the latter two not
enabled -all due to security risk.
If willing to ignore the risk, since these features may need to be enabled
disable and enable as noted

https://wdc.custhelp.com/app/answers...-on-windows-10
"SMB 1.0/CIFS File Sharing Support has been disabled on Windows 10
Windows 10 Fall Creators Update version 1709 and higher."

Windows Credentials
On each device create a Windows Credential for the each ComputerName using
the common username/password(suggesting at the beginning of this post, 1st
item under 'Window 10(both devices)'
e.g. If the common Windows Logon is Cameo(username) and password then create
a credential for that \\ComputerName Enter the \\Computername in the
Network field then enter the username Cameo and password in the dialog
creation box. Repeat this process on both machines until you have 2 Windows
Credentials created on each device(one for each \\ComputerName and both with
same username/pw)

I have done this in the past but Corsair has just had W10 1903
reinstalled and I haven't got that far as yet.

Win10 can still be persnickety about connecting due to device other device
not on, sleeping, hibernating, wifi power management turning off wifi.

At the moment both Corsair and Dell are permanently awake.

For the most part, the devices will be accessible on each device and appear
in File Explorer/Network...if not shown in File Explorer under Network, just
enter the \\Computername in the File Explorer address field to access and
populate the shared folders in File Explorer's Navigation and Display pane.

It hasn't worked in the past. I will try it shortly.

Eric Stevens wrote:
On Tue, 16 Jul 2019 14:02:00 -0400, nospam
wrote:

because he has more hardwired devices than available ports on the
router, or he wants to run one cable to another room which has multiple
devices, rather than run multiple cables to each device.

That's the explanation. Two computers and two printers upstairs.
Router/modem at the fibre termination downstairs.

So how is our network diagram now, for accuracy.

Are we missing anything in the diagram ?

Paul

On Tue, 16 Jul 2019 22:00:28 +1200, Eric Stevens
wrote:

On Tue, 16 Jul 2019 17:34:47 +1200, Eric Stevens
wrote:


I've tried entering the Router to see how it is presently configure
but it is not presently responding to my attempts get in with
192.168.20.1. I will reset things and try again later.

That referred to trying to access the router from Corsair. I've since
tried to contact it from Dell, with no more luck. Everything I've read
says that 192.168.1.1 is the correct address.

I should have written "Everything I've read says that 192.168.20.1 is
the correct address." My copy of the manual says that in six places.
In fact 192.168.1.1 is the correct address and now that I have used
that I can get in.

Now that I can access the router, what should I be looking for?

I can't remembere quite what I did when I received the router: it was
sent to me by Internet provider to replace an earlier less than
satisfactory router. I may have just plugged it in and set it running.
Unlike my earlier router my IP can deal with problems from their end
of the line. Could they have configured it so that I couldn't get at
it from my end? It seems unlikely but I will print and read the manual
and may be talk to their help desk. No doubt more tomorrow.