Losing connectivity when I put in a switch or hub

Hi

I hope someone can give me some suggestions on a problem I'm having.

Basically I have a PC and network printer connected to my D-Link
DSL-G604T Wireless ADSL Modem/Router, which is in turn connected to
the telephone line.

I get a pretty poor signal from it around the house and thought it
might be to do with it being in the study behind a solid wall so I
intended to move it out to the hallway. Rather thatn running cables
for the PC and printer out to it, I planned to connect those items to
a switch or hub and run a single cable out to the router.

Now, I've tried that, and it doesn't seem to work for some reason and
I haven't a clue why not.

I've tried 2 switches and 1 hub but the results are the same,
basically very limited connectivity with what appears to be large
packet losses.

When I do it I can occasionally ping www.google.co.uk but more often
than not at least 50% of the packets sent disappear. I can't even
connect to the routers web browser configuration page at 192.168.1.1.

My PC has an Asus A8V Deluxe motherboard with on-board LAN. It's set
up to use a static IP address of 192.168.1.2 although I tried setting
it up for DHCP at one point and, while it finally managed to lease an
address, the connectivity to the outside world was still poor.

I've also tried using the uplink port on the hub as well as using a
normal port (on the hub and the switches) with a straight through and
a crossover cable and nothing seems to make any difference.

I imagine there's got to be something relatively obvious but important
that I'm missing but I've no idea what; I'm used to sticking switches
and hubs in to expand networks and they just work!

Anyway - any suggestions anyone has would be very much welcomed.

Thanks
John

On Tue, 23 Jun 2009 16:10:22 +0100, John McCabe
<(E-Mail Removed)> wrote:

>Hi
>
>I hope someone can give me some suggestions on a problem I'm having.
>
>Basically I have a PC and network printer connected to my D-Link
>DSL-G604T Wireless ADSL Modem/Router, which is in turn connected to
>the telephone line.

The PC and printer are connected to the Wireless router via wireless
or via cable?

>I get a pretty poor signal from it around the house and thought it
>might be to do with it being in the study behind a solid wall so I

Define "solid wall". What is it made of? Also, "poor signal" seems to
relate to a wireless connection, but throughout your post you don't
mention any wireless connections. Instead, you talk about running a
cable from the PC and printer out to the router. Please clarify.

>intended to move it out to the hallway. Rather thatn running cables
>for the PC and printer out to it, I planned to connect those items to
>a switch or hub and run a single cable out to the router.

So this is a purely cabled environment? Is anything connected via
wireless?

>Now, I've tried that, and it doesn't seem to work for some reason and
>I haven't a clue why not.
>
>I've tried 2 switches and 1 hub but the results are the same,
>basically very limited connectivity with what appears to be large
>packet losses.
>
>When I do it I can occasionally ping www.google.co.uk but more often
>than not at least 50% of the packets sent disappear. I can't even
>connect to the routers web browser configuration page at 192.168.1.1.

What are the IP addresses and netmasks of the LAN side of the router,
the PC, and the printer? Are there any IP conflicts or mismatched
netmasks?

>My PC has an Asus A8V Deluxe motherboard with on-board LAN. It's set
>up to use a static IP address of 192.168.1.2 although I tried setting
>it up for DHCP at one point and, while it finally managed to lease an
>address, the connectivity to the outside world was still poor.

If this is a wired connection and it's having trouble obtaining a DHCP
lease, I would first be suspicious of the router.

To make sure the PC is OK, you could connect the PC directly to the
DSL modem to see if it reliably obtains an IP, Gateway, DNS, etc. Oh
wait, you can't, because you have a combined modem/router.

>I've also tried using the uplink port on the hub as well as using a
>normal port (on the hub and the switches) with a straight through and
>a crossover cable and nothing seems to make any difference.

If the hub or switch is less than a few (5 or so?) years old, it
almost certainly has autosensing ports, so either type of cable should
work. I would stick with straight through patch cables and avoid
crossover cables.

>I imagine there's got to be something relatively obvious but important
>that I'm missing but I've no idea what; I'm used to sticking switches
>and hubs in to expand networks and they just work!
>
>Anyway - any suggestions anyone has would be very much welcomed.
>
>Thanks
>John

Hi Char

First of all thanks for replying.

>>Basically I have a PC and network printer connected to my D-Link
>>DSL-G604T Wireless ADSL Modem/Router, which is in turn connected to
>>the telephone line.

>The PC and printer are connected to the Wireless router via wireless
>or via cable?

Cable.

>>I get a pretty poor signal from it around the house and thought it
>>might be to do with it being in the study behind a solid wall so I

>Define "solid wall". What is it made of?

I think it's breeze-block with plasterboard over it.

> Also, "poor signal" seems to
>relate to a wireless connection, but throughout your post you don't
>mention any wireless connections. Instead, you talk about running a
>cable from the PC and printer out to the router. Please clarify.

Sorry about that. I have another PC elsewhere in the house that's got
a wireless card in it and never gets a very good connection, and I
also use my phone on wi-fi but keep losing the connection. I've used
my phone with other people's wireless systems without the same
problems I have at home, so...

>>intended to move it out to the hallway. Rather thatn running cables
>>for the PC and printer out to it, I planned to connect those items to
>>a switch or hub and run a single cable out to the router.

>So this is a purely cabled environment? Is anything connected via
>wireless?

I use the phone and the other PC wirelessly but, for the purposes of
the problem I'm describing you can probably ignore the wireless
aspect. All I'm trying to do is move the router out of the room it is
currently in while minimising the number of cables that need to be
trailed out.

>>Now, I've tried that, and it doesn't seem to work for some reason and
>>I haven't a clue why not.

>>I've tried 2 switches and 1 hub but the results are the same,
>>basically very limited connectivity with what appears to be large
>>packet losses.

>>When I do it I can occasionally ping www.google.co.uk but more often
>>than not at least 50% of the packets sent disappear. I can't even
>>connect to the routers web browser configuration page at 192.168.1.1.

>What are the IP addresses and netmasks of the LAN side of the router,
>the PC, and the printer? Are there any IP conflicts or mismatched
>netmasks?

The PC is 192.168.1.2/255.255.255.0 and the printer is
192.168.1.100/255.255.255.0. The PC is assigned a static IP address
and the printer gets it through DHCP. The router itself is
192.168.1.1.

>>My PC has an Asus A8V Deluxe motherboard with on-board LAN. It's set
>>up to use a static IP address of 192.168.1.2 although I tried setting
>>it up for DHCP at one point and, while it finally managed to lease an
>>address, the connectivity to the outside world was still poor.

>If this is a wired connection and it's having trouble obtaining a DHCP
>lease, I would first be suspicious of the router.

>To make sure the PC is OK, you could connect the PC directly to the
>DSL modem to see if it reliably obtains an IP, Gateway, DNS, etc. Oh
>wait, you can't, because you have a combined modem/router.

I have no problems when the PC is connected directly in to the router,
it's when it goes through a hub or switch first that things seem to go
wrong.

>>I've also tried using the uplink port on the hub as well as using a
>>normal port (on the hub and the switches) with a straight through and
>>a crossover cable and nothing seems to make any difference.

>If the hub or switch is less than a few (5 or so?) years old, it
>almost certainly has autosensing ports, so either type of cable should
>work. I would stick with straight through patch cables and avoid
>crossover cables.

I've checked the specs of the modem/router and it certainly has
autosensing ports (or so it says).

>>I imagine there's got to be something relatively obvious but important
>>that I'm missing but I've no idea what; I'm used to sticking switches
>>and hubs in to expand networks and they just work!

>>Anyway - any suggestions anyone has would be very much welcomed.

John McCabe wrote:
> Hi Char
>
> First of all thanks for replying.
>
>>> Basically I have a PC and network printer connected to my D-Link
>>> DSL-G604T Wireless ADSL Modem/Router, which is in turn connected to
>>> the telephone line.
>
>> The PC and printer are connected to the Wireless router via wireless
>> or via cable?
>
> Cable.
>
>>> I get a pretty poor signal from it around the house and thought it
>>> might be to do with it being in the study behind a solid wall so I
>
>> Define "solid wall". What is it made of?
>
> I think it's breeze-block with plasterboard over it.
>
>> Also, "poor signal" seems to
>> relate to a wireless connection, but throughout your post you don't
>> mention any wireless connections. Instead, you talk about running a
>> cable from the PC and printer out to the router. Please clarify.
>
> Sorry about that. I have another PC elsewhere in the house that's got
> a wireless card in it and never gets a very good connection, and I
> also use my phone on wi-fi but keep losing the connection. I've used
> my phone with other people's wireless systems without the same
> problems I have at home, so...
>
>>> intended to move it out to the hallway. Rather thatn running cables
>>> for the PC and printer out to it, I planned to connect those items
>>> to a switch or hub and run a single cable out to the router.
>
>> So this is a purely cabled environment? Is anything connected via
>> wireless?
>
> I use the phone and the other PC wirelessly but, for the purposes of
> the problem I'm describing you can probably ignore the wireless
> aspect. All I'm trying to do is move the router out of the room it is
> currently in while minimising the number of cables that need to be
> trailed out.
>
>>> Now, I've tried that, and it doesn't seem to work for some reason
>>> and I haven't a clue why not.
>
>>> I've tried 2 switches and 1 hub but the results are the same,
>>> basically very limited connectivity with what appears to be large
>>> packet losses.
>
>>> When I do it I can occasionally ping www.google.co.uk but more often
>>> than not at least 50% of the packets sent disappear. I can't even
>>> connect to the routers web browser configuration page at
>>> 192.168.1.1.
>
>> What are the IP addresses and netmasks of the LAN side of the router,
>> the PC, and the printer? Are there any IP conflicts or mismatched
>> netmasks?
>
> The PC is 192.168.1.2/255.255.255.0 and the printer is
> 192.168.1.100/255.255.255.0. The PC is assigned a static IP address
> and the printer gets it through DHCP. The router itself is
> 192.168.1.1.
>
>>> My PC has an Asus A8V Deluxe motherboard with on-board LAN. It's set
>>> up to use a static IP address of 192.168.1.2 although I tried
>>> setting it up for DHCP at one point and, while it finally managed
>>> to lease an address, the connectivity to the outside world was
>>> still poor.
>
>> If this is a wired connection and it's having trouble obtaining a
>> DHCP lease, I would first be suspicious of the router.
>
>> To make sure the PC is OK, you could connect the PC directly to the
>> DSL modem to see if it reliably obtains an IP, Gateway, DNS, etc. Oh
>> wait, you can't, because you have a combined modem/router.
>
> I have no problems when the PC is connected directly in to the router,
> it's when it goes through a hub or switch first that things seem to go
> wrong.
>
>>> I've also tried using the uplink port on the hub as well as using a
>>> normal port (on the hub and the switches) with a straight through
>>> and a crossover cable and nothing seems to make any difference.
>
>> If the hub or switch is less than a few (5 or so?) years old, it
>> almost certainly has autosensing ports, so either type of cable
>> should work. I would stick with straight through patch cables and
>> avoid crossover cables.
>
> I've checked the specs of the modem/router and it certainly has
> autosensing ports (or so it says).
>
>>> I imagine there's got to be something relatively obvious but
>>> important that I'm missing but I've no idea what; I'm used to
>>> sticking switches and hubs in to expand networks and they just work!
>
>>> Anyway - any suggestions anyone has would be very much welcomed.

After inserting your switch plug a wired PC into it and ask for a new IP
address using "ipconfig /release" followed by "ipconfig /renew" and see what
your PC shows as it's "new" IP address, provided the PC has been set for
DHCP. I find that until a wired device can work properly through a new
switch I don't even bother messing with the added complexity of a wireless
device.

One thing that can cause problems, if the hub/switch is intelligent and has
the capability of issuing an IP address all on it's own using DHCP then it
may be set to assign an IP address in the same range as your existing
connection. Two devices using 192.168.1.1 on the same network usually won't
work due to routing loops. If the manuals are not specific one easy way to
check this is to unplug the hub/switch from the network. Then plug a wired
PC (set for DHCP) into one of the user ports of the device. Then reboot the
PC or use the "ipconfig /release" followed by "ipconfig /renew" (depending
on the PC's software) and see what IP address the PC comes up with. If it
starts with 169.xxx.xxx.xxx then the device is not providing DHCP and can
most likely be considered a "dumb" hub. If on the other hand you get an IP
address of 192.xxx.xxx.xxx then the device has DHCP capabilities and it is
turned on creating possible conflicts.

For what it's worth when using an actual router or "intelligent" device and
having a PC come up with a 169.xxx.xxx.xxx address usually indicates a
cabling problem between the router and PC or software issues with in the PC
itself provided DHCP has not been disabled on the router.

You don't want your router to be assigning IP values of 192.168.1.xxx AND
your wireless hub doing the same unless they are actually a combined
integrated unit. Then they usually come configured to issue DHCP values
that will not conflict (wired/wireless).

Hopefully some of this rambling will help you or others having similar
problems...

GlowingBlueMist wrote:
> John McCabe wrote:
>> Hi Char
>>
>> First of all thanks for replying.
>>
>>>> Basically I have a PC and network printer connected to my D-Link
>>>> DSL-G604T Wireless ADSL Modem/Router, which is in turn connected to
>>>> the telephone line.
>>> The PC and printer are connected to the Wireless router via wireless
>>> or via cable?
>> Cable.
>>
>>>> I get a pretty poor signal from it around the house and thought it
>>>> might be to do with it being in the study behind a solid wall so I
>>> Define "solid wall". What is it made of?
>> I think it's breeze-block with plasterboard over it.
>>
>>> Also, "poor signal" seems to
>>> relate to a wireless connection, but throughout your post you don't
>>> mention any wireless connections. Instead, you talk about running a
>>> cable from the PC and printer out to the router. Please clarify.
>> Sorry about that. I have another PC elsewhere in the house that's got
>> a wireless card in it and never gets a very good connection, and I
>> also use my phone on wi-fi but keep losing the connection. I've used
>> my phone with other people's wireless systems without the same
>> problems I have at home, so...
>>
>>>> intended to move it out to the hallway. Rather thatn running cables
>>>> for the PC and printer out to it, I planned to connect those items
>>>> to a switch or hub and run a single cable out to the router.
>>> So this is a purely cabled environment? Is anything connected via
>>> wireless?
>> I use the phone and the other PC wirelessly but, for the purposes of
>> the problem I'm describing you can probably ignore the wireless
>> aspect. All I'm trying to do is move the router out of the room it is
>> currently in while minimising the number of cables that need to be
>> trailed out.
>>
>>>> Now, I've tried that, and it doesn't seem to work for some reason
>>>> and I haven't a clue why not.
>>>> I've tried 2 switches and 1 hub but the results are the same,
>>>> basically very limited connectivity with what appears to be large
>>>> packet losses.
>>>> When I do it I can occasionally ping www.google.co.uk but more often
>>>> than not at least 50% of the packets sent disappear. I can't even
>>>> connect to the routers web browser configuration page at
>>>> 192.168.1.1.
>>> What are the IP addresses and netmasks of the LAN side of the router,
>>> the PC, and the printer? Are there any IP conflicts or mismatched
>>> netmasks?
>> The PC is 192.168.1.2/255.255.255.0 and the printer is
>> 192.168.1.100/255.255.255.0. The PC is assigned a static IP address
>> and the printer gets it through DHCP. The router itself is
>> 192.168.1.1.
>>
>>>> My PC has an Asus A8V Deluxe motherboard with on-board LAN. It's set
>>>> up to use a static IP address of 192.168.1.2 although I tried
>>>> setting it up for DHCP at one point and, while it finally managed
>>>> to lease an address, the connectivity to the outside world was
>>>> still poor.
>>> If this is a wired connection and it's having trouble obtaining a
>>> DHCP lease, I would first be suspicious of the router.
>>> To make sure the PC is OK, you could connect the PC directly to the
>>> DSL modem to see if it reliably obtains an IP, Gateway, DNS, etc. Oh
>>> wait, you can't, because you have a combined modem/router.
>> I have no problems when the PC is connected directly in to the router,
>> it's when it goes through a hub or switch first that things seem to go
>> wrong.
>>
>>>> I've also tried using the uplink port on the hub as well as using a
>>>> normal port (on the hub and the switches) with a straight through
>>>> and a crossover cable and nothing seems to make any difference.
>>> If the hub or switch is less than a few (5 or so?) years old, it
>>> almost certainly has autosensing ports, so either type of cable
>>> should work. I would stick with straight through patch cables and
>>> avoid crossover cables.
>> I've checked the specs of the modem/router and it certainly has
>> autosensing ports (or so it says).
>>
>>>> I imagine there's got to be something relatively obvious but
>>>> important that I'm missing but I've no idea what; I'm used to
>>>> sticking switches and hubs in to expand networks and they just work!
>>>> Anyway - any suggestions anyone has would be very much welcomed.
>
> After inserting your switch plug a wired PC into it and ask for a new IP
> address using "ipconfig /release" followed by "ipconfig /renew" and see what
> your PC shows as it's "new" IP address, provided the PC has been set for
> DHCP. I find that until a wired device can work properly through a new
> switch I don't even bother messing with the added complexity of a wireless
> device.
>
> One thing that can cause problems, if the hub/switch is intelligent and has
> the capability of issuing an IP address all on it's own using DHCP then it
> may be set to assign an IP address in the same range as your existing
> connection. Two devices using 192.168.1.1 on the same network usually won't
> work due to routing loops. If the manuals are not specific one easy way to
> check this is to unplug the hub/switch from the network. Then plug a wired
> PC (set for DHCP) into one of the user ports of the device. Then reboot the
> PC or use the "ipconfig /release" followed by "ipconfig /renew" (depending
> on the PC's software) and see what IP address the PC comes up with. If it
> starts with 169.xxx.xxx.xxx then the device is not providing DHCP and can
> most likely be considered a "dumb" hub. If on the other hand you get an IP
> address of 192.xxx.xxx.xxx then the device has DHCP capabilities and it is
> turned on creating possible conflicts.
>
> For what it's worth when using an actual router or "intelligent" device and
> having a PC come up with a 169.xxx.xxx.xxx address usually indicates a
> cabling problem between the router and PC or software issues with in the PC
> itself provided DHCP has not been disabled on the router.
>
> You don't want your router to be assigning IP values of 192.168.1.xxx AND
> your wireless hub doing the same unless they are actually a combined
> integrated unit. Then they usually come configured to issue DHCP values
> that will not conflict (wired/wireless).
>
> Hopefully some of this rambling will help you or others having similar
> problems...
>
>
Do you set the wireless channel or is it set for auto
How many other networks are in your area a "N band router will blow most
G routers" bonkers

I use BgInfo from
http://technet.microsoft.com/en-us/s.../bb897557.aspx
to display IP on screen
setup a batch file and place a shortcut on screen
just click on shortcut to reissue network stats great for a laptop

****************************batch file
ipconfig /release
ipconfig /renew
start "" "G:\program files\Bginfo.exe"
***********************************end

call file what ever you want I use NewIP.bat

next there are several programs around that plot signial strength over
time see if you can find one and see what happens

one of my Dlink boxes drops signal every two hour by its self traced
problem to a metal bar about 24 inches away wich was reflecting signal
back to unit and over powering transmitter control had to move unit 4
feet to stop this

try setting channel start at top channel and move down two channels at a
time every week
you might find a better channel for your location

hope this helps

On Wed, 24 Jun 2009 10:56:30 +0100, John McCabe
<(E-Mail Removed)> wrote:

>All I'm trying to do is move the router out of the room it is
>currently in while minimising the number of cables that need to be
>trailed out.
>
>The PC is 192.168.1.2/255.255.255.0 and the printer is
>192.168.1.100/255.255.255.0. The PC is assigned a static IP address
>and the printer gets it through DHCP. The router itself is
>192.168.1.1.

That all looks good.

>I have no problems when the PC is connected directly in to the router,
>it's when it goes through a hub or switch first that things seem to go
>wrong.

Bad Ethernet cable? Do you have a spare cable you can swap with?

Also, simplify things by connecting just two devices at first, whether
it's the networked printer and the PC, or the PC and the router. Do
things work as expected then? What do the status lights tell you
(beside the Ethernet port on the PC and usually on the front of the
switch/hub). Is the Link light solidly lit? Does the Activity light
blink when data is being passed, and otherwise mostly off?

Lastly, could this be a speed/duplex mismatch between the various
Ethernet devices?

>I've checked the specs of the modem/router and it certainly has
>autosensing ports (or so it says).

To help rule out the concern of multiple DHCP servers on the network,
as Glowing Blue Mist suggested, please provide the make and model of
the switches and hub you've tried. I can't say I've ever seen a hub or
switch with DHCP capabilities, but I tend to stay in the lower half of
the various product lines and that's a bit of a premium feature when
you're talking about hubs and switches.

On Wed, 24 Jun 2009 10:56:30 +0100, John McCabe wrote:


> Sorry about that. I have another PC elsewhere in the house that's got a
> wireless card in it and never gets a very good connection, and I also
> use my phone on wi-fi but keep losing the connection. I've used my phone
> with other people's wireless systems without the same problems I have at
> home, so...

Two things come to mind;
1) you have steel in the line of sight of the wifi; stairs, bearers,
chimney, racking, etc
2) another device is corrupting the channel being used. Try changing it
to others. Some guy reported his electric tooth brush was screwing up his
wifi (used it to report brush pressure or something to a base unit).

The message <(E-Mail Removed)>
from Char Jackson <(E-Mail Removed)> contains these words:

> On Wed, 24 Jun 2009 10:56:30 +0100, John McCabe
> <(E-Mail Removed)> wrote:

> >All I'm trying to do is move the router out of the room it is
> >currently in while minimising the number of cables that need to be
> >trailed out.
> >
> >The PC is 192.168.1.2/255.255.255.0 and the printer is
> >192.168.1.100/255.255.255.0. The PC is assigned a static IP address
> >and the printer gets it through DHCP. The router itself is
> >192.168.1.1.

> That all looks good.

> >I have no problems when the PC is connected directly in to the router,
> >it's when it goes through a hub or switch first that things seem to go
> >wrong.

> Bad Ethernet cable? Do you have a spare cable you can swap with?

> Also, simplify things by connecting just two devices at first, whether
> it's the networked printer and the PC, or the PC and the router. Do
> things work as expected then? What do the status lights tell you
> (beside the Ethernet port on the PC and usually on the front of the
> switch/hub). Is the Link light solidly lit? Does the Activity light
> blink when data is being passed, and otherwise mostly off?

> Lastly, could this be a speed/duplex mismatch between the various
> Ethernet devices?

> >I've checked the specs of the modem/router and it certainly has
> >autosensing ports (or so it says).

> To help rule out the concern of multiple DHCP servers on the network,
> as Glowing Blue Mist suggested, please provide the make and model of
> the switches and hub you've tried. I can't say I've ever seen a hub or
> switch with DHCP capabilities, but I tend to stay in the lower half of
> the various product lines and that's a bit of a premium feature when
> you're talking about hubs and switches.

A DHCP server is normally only found on routers. Switches (forget about
hubs - they've been supplanted by switches for many years, even on SoHo
kit) don't provide a DHCP serving function.

However, the OP seems to have it arse about face regarding what's
statically configured and what uses DHCP. Things like client PCs are
best set up using DHCP assigned IP addresses and items like servers
(print or file) are best set up with a static IP address _outside_of_
the DHCP IP pool scope (but within the subnet range).

The OP might try setting the router's DHCP scope to something like 1 to
100 and assign the server and printer IP addresses in the range 101 to
254 (assuming the router's own IP isn't on 254). I'm not certain how the
DHCP server deals with static IPs within its scope (badly, I suspect) so
a less fraught arrangement would be as suggested above. ;-)

HTH

--
Regards, John.

Please remove the "ohggcyht" before replying.
The address has been munged to reject Spam-bots.

On Wed, 24 Jun 2009 16:36:24 +0100, Johnny B Good
<(E-Mail Removed)> wrote:

> A DHCP server is normally only found on routers. Switches (forget about
>hubs - they've been supplanted by switches for many years, even on SoHo
>kit) don't provide a DHCP serving function.

I agree. That's why I asked about make/model info.

> However, the OP seems to have it arse about face regarding what's
>statically configured and what uses DHCP. Things like client PCs are
>best set up using DHCP assigned IP addresses and items like servers
>(print or file) are best set up with a static IP address _outside_of_
>the DHCP IP pool scope (but within the subnet range).

While that's frequently the way it's done, it's not going to make the
slightest bit of difference toward solving the OP's problem, so I
didn't dwell there.

On Wed, 24 Jun 2009 08:09:20 -0400, Smiles
<(E-Mail Removed)> wrote:

>Do you set the wireless channel or is it set for auto
>How many other networks are in your area a "N band router will blow most
>G routers" bonkers

I really do appreciate your input, but we're getting a bit too caught
up on the wireless side. The problem with low signal strength etc is a
side issue that is the reason why I want to put the hub or switch in.
The problem I'm confused about is why things are not working when I
put the hub/switch in so ignore the wireless aspect for the moment.

The switches and hubs I've used have been very simple unmanaged ones
that I've borrowed from work and that I use at work with no problems.
They don't have any intelligence in the form of DHCP servers or
anything.

When I tried DHCP on my wired PC, at the second attempt it was
assigned 192.168.1.102 (my router is set up to assign DHCP addresses
from 192.168.1.100 upwards, and my printer already had .100 and .101
leased.

John