Subnet newb needs help

[ShearMe]

Alright, so I made the mistake of setting some devices to a subnet mask of 255.255.255.254

 

What windows IP settings do I need to employ to actually be able to reach the webportal of the devices to reconfigure their network settings?

[flashiling]

3 minutes ago, ShearMe said:

Alright, so I made the mistake of setting some devices to a subnet mask of 255.255.255.254

 

What windows IP settings do I need to employ to actually be able to reach the webportal of the devices to reconfigure their network settings?

i mean it depends on the ip's that you own/pay for.

as a device with that subnet mask only has space for itself on the subent.

don't you have physical access to the devices

[ShearMe]

1 minute ago, flashiling said:

i mean it depends on the ip's that you own/pay for.

as a device with that subnet mask only has space for itself on the subent.

don't you have physical access to the devices

Yes, I have physical access to the devices

[Lurick]

1 minute ago, flashiling said:

as a device with that subnet mask only has space for itself on the subent.

Actually, a /31 mask allows for point to point connectivity so one host would be .0 and the other .1 if you do 192.168.0.0/31 as an example. OP would need to connect directly to the device and configure the other available IP in that subnet on their device to access it to fix this.

[flashiling]

if you can access the device and plug in a keyboard/mouse, just edit the subnet to a 255.255.255.0 this would put them in the same subnet as all other devices which ip starts with (ip used is purely random and to make an example) 192.168.0.XXX

[flashiling]

2 minutes ago, Lurick said:

Actually, a /31 mask allows for point to point connectivity so one host would be .0 and the other .1 if you do 192.168.0.0/31 as an example. OP would need to connect directly to the device and configure the other available IP in that subnet on their device to access it to fix this.

oh, i must be remembering incorrectly.

but wouldn't a /31 allow one host since the two others would be occupied for the network/broadcast adresses

[ShearMe]

Devices configured with the /31 mask do not have keyboard/mouse capability. Can only factory reset or "log in" through a web portal to change settings.

 

 

[Lurick]

Just now, flashiling said:

oh, i must be remembering incorrectly.

but wouldn't a /31 allow one host since the two others would be occupied for the network/broadcast adresses

A /31 is actually 2 addresses and is just a "broadcast" and "network" address but instead of leaving them "idle" in a sense you use both of those for each end of the link. It's used a lot in enterprise settings to conserve address space so you're not burning 4 addresses with a /30 but just 2 with a /31 since in most cases you don't need the other two

[Lurick]

Just now, ShearMe said:

Devices configured with the /31 mask do not have keyboard/mouse capability. Can only factory reset or "log in" through a web portal to change settings.

 

 

You would have to reset them to factory defaults or plug in a laptop or something, set the other side to the other address in the subet of /31 and then access it via browser on your device.

[Oshino Shinobu]

2 minutes ago, flashiling said:

oh, i must be remembering incorrectly.

but wouldn't a /31 allow one host since the two others would be occupied for the network/broadcast adresses

For typical subnetting, yes. 

 

However, for a point to point link, the broadcast address doesn't really apply as there's only one address for it to "broadcast" to. 

 

This video explains to pretty well:

 

 

[flashiling]

Just now, Lurick said:

A /31 is actually 2 addresses and is just a "broadcast" and "network" address but instead of leaving them "idle" in a sense you use both of those for each end of the link. It's used a lot in enterprise settings to conserve address space so you're not burning 4 addresses with a /30 but just 2 with a /31 since in most cases you don't need the other two

oh, will remember that as i'm going back to school in a few weeks

[ShearMe]

Just now, Lurick said:

You would have to reset them to factory defaults or plug in a laptop or something, set the other side to the other address in the subet of /31 and then access it via browser on your device.

 

Ok, so I'm connected with a laptop... what's the "other address" I should be using for the laptop? 10.60.13.104 is the device, for example

[Lurick]

Just now, flashiling said:

oh, will remember that as i'm going back to school in a few weeks

Yah, it was something I didn't see in school either, they stopped at /30s for subnetting and then /32 for host and a lot of older devices would actually warn you if you configured a /31 subnet because it wasn't as common 5-10 years ago.

[Lurick]

Just now, ShearMe said:

 

Ok, so I'm connected with a laptop... what's the "other address" I should be using for the laptop? 10.60.13.104 is the device, for example

In that case it would be 10.60.13.105

 

I would use this to make it easy and just set the mask to /31 and put in the device IP and calculate what you need to set your laptop/PC to:

https://www.calculator.net/ip-subnet-calculator.html

[Oshino Shinobu]

1 minute ago, ShearMe said:

 

Ok, so I'm connected with a laptop... what's the "other address" I should be using for the laptop? 10.60.13.104 is the device, for example

10.60.13.105/31

[ShearMe]

Well, crap. +1 is what I have been trying to use for the past half hour. Guess I'll bite the bullet and get those resets rolling.

 

Thanks dudes.