reserved IP address has no effect

[newway]

Recently swithed to Sky, Sky Hub (SR123) working. 

I need to have fixed IP address for one of my devices serving as a home server. In the router web interface UI, I go to

"Connected Devices > Devices"  and clicked "Edit" on the target device, clicked "Reserved IP" and "Save"

After saving, the Device List still shows the device as "DHCP" in the "DHCP/Reserved IP" column. 

And if I click "Edit" again, I can see it is still "DHCP" configuration, as if the saving has no effect.

What did I do wrong? 

P.S. I cannot set DHCP settings using the Sky App, and what's even worse/weird, Sky App connected devices shows every device as a different ip address 192.168.0.x, instead of 192.168.1.x that I set via the Web interface

[Chrisee]

@newway the web interface on the SR213 Sky Max hub has very limited use. Most of the settings have limited use with the customer settings being moved to the My Sky app..

By default Sky always use the internal address range of 192.268.0.1 to 192.168.254 with a sunbnet mask of 255.255.255.0 the DHCP server on my unit and I presume yours allocates address  from 192.168.0.2 to 192.168.0.100. The hub' gateway address is 192,168.0.1

Have you edited this screen ti switch the range to 192.168.1.x? If you did the greyed out DHCP range details change?

I

By far the easiest method of having a fixed IP address is to assign the device an address such as 192.168.0.200 ie outside the range of the DHCP server. Personally I would nit try to changecthe internal address range unless it is vital.

[Me134]

@Chrisee Did you not change your ending address to 192.168.0.100. previously? Mine is set to 192.168.0.253.

[Chrisee]

@Me134 it is possible I did. @newway limiting the DHCP range and assigning fixed IP addresses is an option the will work.

[newway]

I have changed the LAN IP range, below

 I suspect the Sky APP somehow is not realtime refreshed and it is showing my old up range. I did try manually assign an IP outside of this DHCP range e.g 192.168.1.200 in the reserved ip field, but a pop up come up said something like "this ip is out of dhcp range"

interestingly, I tried and the reserved ip works on my iPhone connected via WiFi, but I highly doubt this limits to WiFi devices but not LAN devices 

[newway]

It's been a month and no solution yet, in summary:

1. in the router web UI, changing the device from "DHCP" to "Reserved IP" has no effect, no error message, but it stays as "DHCP"
2. I can change some other device from "DHCP" to "Reserved IP", it is unclear why
3. my DHCP range is 192.168.1.2 to 192.168.1.99 ,   if I choose "Reserved IP" and manually set ip address outside this range, I'll get an error pop up not allowing me to specify out-of-range IPs

Going forward I'll either set the DHCP leasetime to `forever` or attempt to setup static IP on the client side (Ubuntu)

[Deb3000]

There are three ways to set an IP address:

Dynamic/automatic…DHCP issues an address from the pool to the device when it starts up.

Reserved…DHCP still issues an address but the same address each time, (using the MAC address to identify the device).  Reserved addresses are within the range issued by DHCP.  Reserved addresses can be notoriously flaky.  One place I worked wouldn’t allow them for that reason.  Yet another place I worked used reserved every time a fixed address was needed and never had any problems with them.

Static…The address is set manually on the device itself.  Nothing to do with DHCP, so this address has to be outside the range DHCP is issuing.

A server is usually given a static address.  Can you set the address on the device itself?  A static address is usually far better.

[Deb3000]

I've just spotted another issue.

If you are using 255.255.255.0 for the mask the first three octets in the address must be the same.  In other words, 192.168.0 and 192.168 1 are separate networks, so they will not talk to each other.  Making the mask 255.255.0.0 would put them both in the same network.

[newway]

Yes, all my ip address were in 192.168.1.x same subnet 

[Chrisee]

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@newway wrote:

It's been a month and no solution yet, in summary:

1. in the router web UI, changing the device from "DHCP" to "Reserved IP" has no effect, no error message, but it stays as "DHCP"
2. I can change some other device from "DHCP" to "Reserved IP", it is unclear why
3. my DHCP range is 192.168.1.2 to 192.168.1.99 ,   if I choose "Reserved IP" and manually set ip address outside this range, I'll get an error pop up not allowing me to specify out-of-range IPs

Going forward I'll either set the DHCP leasetime to `forever` or attempt to setup static IP on the client side (Ubuntu)

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@newway you cannot reserve an IP address which is outside the range of the DHCP server but there is no need to in the first place.  If you assign a fixed IP address of say 192.168.1.220 to a device it can connect to the router as it is in the correct subnet as defined by the gateway and the subnet mask but the DHCP cannot issue that address to another device. Its up to you to make sure you use different fixed IP addresses for each device.