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Uverse Subnets & DHCP


Uverse Subnets & DHCP

ATT Friday forced an upgrade on us from a DSL Line to Uverse Internet.


Our prior LAN settings were simple enough and worked great with the ATT Motorola modem/router.


The Router Access was (having been changed from the default

Subnet mask

DHCP Start Address

DHCP End Address


In trying to change the new router's settings:

Home Network> Subnets & DHCP > Private LAN Subet > Device IPv4 Address


When the preferred address is entered ( we encounter an error of "Address must be on network ("


Was hoping the setup would be as simple as the previous time?  Any help?


Message 1 of 11
Former Employee

Re: Uverse Subnets & DHCP

It sounds like your subnet mask is not correct.


default for (what used to be) a Class C address is the familiar ""


If, for some reason, you subnetted that address, or if the provider gave you a small block of addresses (if you tell us how many, we can tell you the correct subnet mask), the mask will be something like or



Message 2 of 11

Re: Uverse Subnets & DHCP

you are right, I notice that the machine I am on that has been assigned an IP address using the DHCP shows the subnet mask as


The current settings on the NVG510 read:


Subnets & DHCP>


Device IPv4 Address:

Subnet Mask:

DHCPv4 Start Address:

DHCPv4 End Address:


again, I'd just like to alter the Device Address to and change the start and end addresses.




Message 3 of 11

Re: Uverse Subnets & DHCP

Message 4 of 11

Re: Uverse Subnets & DHCP

Why are you trying to use 195.10.10.x on your LAN? These are registered IP addresses that are used in Europe, they're not supposed to be assigned to your LAN.
Message 5 of 11

Re: Uverse Subnets & DHCP

largely because they have been this way for years. 1/2 the machines on the network use a fixed IP address, printers are setup with fixed IP addresses etc. It is an effort to change all of the machines.
Message 6 of 11

Re: Uverse Subnets & DHCP

Not sure why it should matter why my private LAN settings are?
Message 7 of 11

Re: Uverse Subnets & DHCP

Certainly appreciate all the help.


Here is as much detail as I can think of (not networking expert).  Trying to get things back as close to OLD SETTINGS as possible (after DSL switched out for uVerse).



Netopia-3000, model 3347-02, software version 7.8.1r2


LAN IP Interface >

Enable Interface - checked

IP Address (changed from default of

IP Netmask

Restrictions - none


no advanced settings, no IP Subnets


DHCP Server >

Server mode - Server

Starting IP Address

Ending IP Address

Lease Period 01:00:00:00


WAN IP Interfaces

PPP over Ethernet vcc1

Enable Gateway option -checked

Interface Type PPP vcc1


WAN IP Interface (PPP over Ethernet vcc1) settings >

Enable Interface - checked

Address mapping (NAT) - checked

Restrictions - none

ISP Username xxxx

ISP Password xxxx

Connection Type - always on



Domain Name att.net

Primary DNS

Secondary DNS



NEW SETTINGS (ATT UVERSE, as per ATT installer departure from premisis)


Device and Broadband settings as per ATT installer & working.


Home Network Status >
Device IPv4 Address192.168.1.254
DHCPv4 Netmask255.255.255.0
DHCPv4 Start Address192.168.1.64
DHCPv4 End Address192.168.1.253
DHCP Leases Available197
DHCP Leases Allocated6
DHCP Primary PoolPublic


Configure > ports 1-4 all auto

Wireless - working

Mac Filters - none assigned


Private LAN Subnet

Device IPv4 Address
Subnet Mask
DHCPv4 Start Address
DHCPv4 End Address


Is it possible to replicate what we had previously "OLD SETTINGS" and have the DHCP server issuing IP addresses in the 195.10.10.xxx ranges?  When trying to do so, error message is.


Address must be on network (



Message 8 of 11
Accepted by (Expert)
Accepted by SomeJoe7777
‎09-30-2015 1:39 AM

Re: Uverse Subnets & DHCP

@lanhlp wrote:
Not sure why it should matter why my private LAN settings are?


Because 195.10.10.x is not a private LAN.  Those IP addresses belong to someone else, assigned to them by RIPE (IP addressing registry for Europe).  If you were to try to pull up a web site hosted by the company that owns those IP addresses, you wouldn't be able to because your internal routing wouldn't properly route the request.


IP addressing is handled by international numbering authorities and is very specific in the way they're handed out.  You can't just "pick" some addresses at random and use them.  It doesn't matter if your network has been set up this way for years, that still doesn't make it any less wrong.


Unless you have hundreds of devices on static IP addresses, renumbering a network doesn't take very long.  I have at least 10 devices on static IPs in my house (another 10-15 on DHCP), and renumbering would take me less than an hour.


RFC1918 specifies that you have 3 IP address ranges that are designated for private IP addressing that you can use however you see fit and can subnet however you see fit.  AT&T allows you to use 2 of those 3 ranges: is one block.  Typically this is subnetted into class C-sized address space, like is the 2nd block.  Same rules apply, usually it's subnetted into class C-sized address space.


As an example, you could use  This means that you would configure as follows:


Router (2Wire gateway):

Subnet masl:

Static IP addresses: through

DHCP range: through


For static IP devices, just pick an IP address in the static range.  All of those devices also get as their subnet mask and as their gateway.  For DNS, you can use the 2Wire gateway itself (, or if you want you can use Google DNS ( and or OpenDNS ( and



Tags (1)
Message 9 of 11

Re: Uverse Subnets & DHCP

I tried this and I get the error Address must be on network ( Device IPv4 Address Subnet Mask DHCPv4 Start Address DHCPv4 End Address
Message 10 of 11

Re: Uverse Subnets & DHCP

Sorry I meant for the start and end I used: DHCPv4 Start Address DHCPv4 End Address
Message 11 of 11
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