How to determine DHCP range?

I have found that computers not seeing each other has nothing to do with their IP addresses. I set most things to static because someone suggested it one time but that did not help at all.

You can easily adjust the range


You can easily set static addresses as long as there is no conflict.

MisterEd said:

I have found that computers not seeing each other has nothing to do with their IP addresses. I set most things to static because someone suggested it one time but that did not help at all.

Did you find something that did help?

Is "Reserved IP" the same as a static IP?

CluelessInSeatl said:

Windows Version: 20H2

I try to keep my PC and my laptop connected on a Windows 10 wired home network, via an ARRIS TG862G Router supplied by my ISP (Comcast/Xfinity).

I say "I try," because the performance of my home network is spotty at best. Sometimes the laptop can see the PC, but not vice versa. Sometimes the PC can see the laptop but not vice versa. Sometimes the PC and laptop can't even see themselves on the network.

An acquaintance on a local BBS has suggested that I try assigning fixed IPs to the devices on my network, and specified that I "fix the addresses to a value which isn't in the DHCP range."

I've taken a look at the router settings, and can't find where it shows the DHCP range. I'd be grateful if someone here could help me figure this out.

Will in Seattle
a.k.a. "Clueless"

P.S. I just found this on the Xfinity User Forum :

"I understand we cannot have static IP addresses with xfinity residential accounts. Is this correct? If we can't do this can we at least specify a range of IPs to exclude from the DHCP pool? How would I go about doing this?"

"Correct. Only Business Class subscribers can get a statically assigned WAN / public IP addy. "

Does that mean that I won't be able to assign fixed IP addresses to the devices on my home network?

OK, just to clarify the basics:

Your router presents an IP address to the outside Internet which is unique and usually issued by your internet provider when you connect. You don't see this (or care about it usually) and it has no effect on the devices in your setup at home. This is called a WAN or Public IP address and as I say, you don't need to worry about it or if it is static or not.

Secondly, there are IP addresses for the devices in your setup at home, which you do need to worry about. It is these devices that can be automatically given IP addresses by your router (using DHCP) when they connect to your network and can change every time a device connects.

These devices can also be configured to have fixed - or static - IP addresses instead. That way, whenever they connect they have the same IP addresses. This can be useful if you want to access a device using it's IP address.

Your router is setup to only give your devices an IP address out of a certain range of IP addresses when using DHCP, so that if you want some static IP addresses too it doesn't accidently use the same one twice.

If you want to use a static IP address that is within the range of addresses that can be assigned using DHCP then you can reserve them, meaning that the router will then not assign them to a device using DHCP.

Hope that wasn't too simplistic for you, but I know it's easy to assume that someone knows all this stuff and when they don't it can be really daunting!

CluelessInSeatl said:

Did you find something that did help?

Is "Reserved IP" the same as a static IP?

I have a couple ways to help when computers don't show up in Network. I describe these in the following post

Laptop can't see main PC even though PC can see laptop (Post #8)
Laptop can't see main PC even though PC can see laptop

Note these things only help if the computer is set up correctly to show up in the network but for some reason is not being seen. You can tell a computer is set up right by trying to ping it.

For example, right now I can't see the computer DarkMatter on the Network. However, I can ping its IP address as shown below.

BTW, even though it is not showing up I can still access it by using the shortcut to it.

Code:

C:\ping 10.0.0.2

Pinging 10.0.0.2 with 32 bytes of data:
Reply from 10.0.0.2: bytes=32 time=9ms TTL=128
Reply from 10.0.0.2: bytes=32 time=5ms TTL=128
Reply from 10.0.0.2: bytes=32 time=6ms TTL=128
Reply from 10.0.0.2: bytes=32 time=8ms TTL=128

Ping statistics for 10.0.0.2:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 5ms, Maximum = 9ms, Average = 7ms

Right or wrong "Reserved IP" and "Static IP" are used interchangeability. Technically they are not the same. I used "Reserved IP" because that is what Comcast calls "Static IP" in their router configuration.

Even though Reserved IPs have not helped with whether my computers are seen or not on my network I continue to use them because sometimes it helps me for computers to have a fixed IP address. Two examples are:
1. I always know a computers IP address so I know what value to use when I need to ping it
2. I have some computer that are set up for remote access. The configuration software requires a Static IP address.

I just discovered something which may be a clue to why my PC (named "Lenny") vanished from my home network. I just tried to connect from the laptop to the PC using Windows Remote Desktop, and got this error message: "The identity of the remote computer cannot be verified. Do you want to connect anyway?"



Could this be the reason the PC (a.k.a. "Lenny") has disappeared from my network?

BTW, in spite of the warning, I chose to "connect anyway" and was able to access the desktop on the PC with no problems. I tried to "Install Certificate," but just kept going in circles. Perhaps if I could figure out how to complete this step, my PC would reappear on my network. Should I start a separate thread seeking help with the "Install Certificate" process?

Also, I just checked the advanced network settings, and both computers have network discovery turned on, and "automatic setup" is checked on both machines.

I should probably have mentioned at the outset that I'm not very tech savvy, and I have to confess that I can't always comprehend the technical jargon and acronyms in the replies to my query, so I have to spend some time Googling on the web to figure out what they mean.

Will in Seattle
a.k.a. "Clueless"