How To: Linksys DHCP assigns address based on MAC?

In article <030720091327468163%nospam@home.com>,
YA MacUser <nospam DeleteThis @home.com> wrote:

> Greetings and thanks for reading this.
> With D-Link consumer routers, it is easy to have the DHCP server always
> assign the same LAN address to a given MAC number so port forwarding
> will go to the computer with that LAN address.
> I need to do this to a Linksys WRT54G router but can't find a
> recognizable page in the setup. Where to control the DHCP server?
> Kind regards

Linksys router, NAT, and firewall solutions are pathetic. No features,
no throughput, and very prone to crashing. I don't think you'll find a
better solution than ditching it.

As a temporary solution, you can give the computers static IP addresses
inside the subnet but outside the DHCP range. The Linksys probably only
handles 25 DHCP addresses so plenty are left for manual assignment even
in a /24 subnet.

--
I will not see your reply if you use Google.

On Fri, 3 Jul 2009 23:09:07 -0400, Gene E. Bloch wrote
(in article <wizyxh36qmpl.1mggm4zi65arb$.dlg@40tude.net>):

> On Fri, 03 Jul 2009 13:27:46 -0700, YA MacUser wrote:
>
>> Greetings and thanks for reading this.
>> With D-Link consumer routers, it is easy to have the DHCP server always
>> assign the same LAN address to a given MAC number so port forwarding
>> will go to the computer with that LAN address.
>> I need to do this to a Linksys WRT54G router but can't find a
>> recognizable page in the setup. Where to control the DHCP server?
>> Kind regards
>
> Can't you tell the computer with that MAC address to use a fixed IP
> address?
>
> That's the way it works in Windows (and it's easy to do).
>
>

If he uses a fixed IP that's within the DHCP pool, the router might allocate
that IP to something else. That would be bad. Most routers allow for IPs to
be reserved for particular MAC addresses. The Linksys User Guide details how.
Chapter 8, IIRC.

--
email to oshea dot j dot j at gmail dot com.

In article <h2movb036c DeleteThis @news6.newsguy.com>,
J.J. O'Shea <try.not.to DeleteThis @but.see.sig> wrote:

> On Fri, 3 Jul 2009 23:09:07 -0400, Gene E. Bloch wrote
> (in article <wizyxh36qmpl.1mggm4zi65arb$.dlg@40tude.net>):
>
> > On Fri, 03 Jul 2009 13:27:46 -0700, YA MacUser wrote:
> >
> >> Greetings and thanks for reading this.
> >> With D-Link consumer routers, it is easy to have the DHCP server always
> >> assign the same LAN address to a given MAC number so port forwarding
> >> will go to the computer with that LAN address.
> >> I need to do this to a Linksys WRT54G router but can't find a
> >> recognizable page in the setup. Where to control the DHCP server?
> >> Kind regards
> >
> > Can't you tell the computer with that MAC address to use a fixed IP
> > address?
> >
> > That's the way it works in Windows (and it's easy to do).
> >
> >
>
> If he uses a fixed IP that's within the DHCP pool, the router might allocate
> that IP to something else. That would be bad. Most routers allow for IPs to
> be reserved for particular MAC addresses. The Linksys User Guide details how.
> Chapter 8, IIRC.

So he should use a fixed IP that's NOT within the DHCP pool.

I have a WRT54G, and AFAIK it doesn't have a way to configure static
MAC->IP mappings for the DHCP server. Maybe this can be added with
DD-WRT firmware.

--
Barry Margolin, barmar DeleteThis @alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

On Sat, 4 Jul 2009 02:00:30 -0400, Barry Margolin wrote
(in article <barmar-DA6257.02003004072009.TakeThisOut@news.eternal-september.org>):

> In article <h2movb036c.TakeThisOut@news6.newsguy.com>,
> J.J. O'Shea <try.not.to.TakeThisOut@but.see.sig> wrote:
>
>> On Fri, 3 Jul 2009 23:09:07 -0400, Gene E. Bloch wrote
>> (in article <wizyxh36qmpl.1mggm4zi65arb$.dlg@40tude.net>):
>>
>>> On Fri, 03 Jul 2009 13:27:46 -0700, YA MacUser wrote:
>>>
>>>> Greetings and thanks for reading this.
>>>> With D-Link consumer routers, it is easy to have the DHCP server always
>>>> assign the same LAN address to a given MAC number so port forwarding
>>>> will go to the computer with that LAN address.
>>>> I need to do this to a Linksys WRT54G router but can't find a
>>>> recognizable page in the setup. Where to control the DHCP server?
>>>> Kind regards
>>>
>>> Can't you tell the computer with that MAC address to use a fixed IP
>>> address?
>>>
>>> That's the way it works in Windows (and it's easy to do).
>>>
>>>
>>
>> If he uses a fixed IP that's within the DHCP pool, the router might
>> allocate
>> that IP to something else. That would be bad. Most routers allow for IPs to
>> be reserved for particular MAC addresses. The Linksys User Guide details
>> how.
>> Chapter 8, IIRC.
>
> So he should use a fixed IP that's NOT within the DHCP pool.

Yes. IIRC Linksys routers usually set the DHCP pool to be from 192.168.1.10
on up to 192.168.1.254. The router itself is usually 192.168.1.1, and of
course 192.168.1.0 and 192.168.1.255 can't be used, so that leaves
192.168.1.2 to 192.168.1.9 available for use.

>
> I have a WRT54G, and AFAIK it doesn't have a way to configure static
> MAC->IP mappings for the DHCP server. Maybe this can be added with
> DD-WRT firmware.

I could be wrong about this, but I'd be surprised if I were as that would
make Linksys the only vendor which doesn't support reserved IPs, which is a
standard TCP feature. Certainly the routers I have at home and at the office
support reserved IPs. I use them all the time for printers, servers, NAS
boxes, and laptops.


--
email to oshea dot j dot j at gmail dot com.

On Sat, 4 Jul 2009 03:34:25 -0400, Kevin McMurtrie wrote
(in article <4a4f0602$0$95508$742ec2ed@news.sonic.net>):

> In article <030720091327468163%nospam@home.com>,
> YA MacUser <nospam DeleteThis @home.com> wrote:
>
>> Greetings and thanks for reading this.
>> With D-Link consumer routers, it is easy to have the DHCP server always
>> assign the same LAN address to a given MAC number so port forwarding
>> will go to the computer with that LAN address.
>> I need to do this to a Linksys WRT54G router but can't find a
>> recognizable page in the setup. Where to control the DHCP server?
>> Kind regards
>
> Linksys router, NAT, and firewall solutions are pathetic. No features,
> no throughput, and very prone to crashing. I don't think you'll find a
> better solution than ditching it.
>
> As a temporary solution, you can give the computers static IP addresses
> inside the subnet but outside the DHCP range. The Linksys probably only
> handles 25 DHCP addresses so plenty are left for manual assignment even
> in a /24 subnet.
>
>

I didn't think that Linksys was _that_ bad. Not fully baked, yes, but missing
key features? Maybe I'm spoiled by using real routers...

--
email to oshea dot j dot j at gmail dot com.

On 2009.07.04 07:34:25,
the amazing <kevinmcm DeleteThis @sonic.net> declared:

<snip!>

> Linksys router, NAT, and firewall solutions are pathetic. No features,
> no throughput, and very prone to crashing. I don't think you'll find a
> better solution than ditching it.

I've been using a Linksys BEFSR for quite a while, and
it seems to do the job OK. On the BEFSR you specify what
IP range you let the DHCP server control. I only let it
control a small number, so guests can plug into the net.
Our two Apples, and our backup drive, claim their own IPs.

But obviously my notion that the Linksys does everything
I expect a router to do doesn't have much grounding, since
the only router I've ever had is a Linksys Eventually
I'll have to replace it. Is there consensus about which
brands are good? Maybe I should ask whether there's a web
site that has ratings....

> As a temporary solution, you can give the computers static IP addresses
> inside the subnet but outside the DHCP range. The Linksys probably only
> handles 25 DHCP addresses so plenty are left for manual assignment even
> in a /24 subnet.


--
Nollaig MacKenzie
http://www.amhuinnsuidhe.net

On Sat, 4 Jul 2009 10:45:33 -0400, Nollaig MacKenzie wrote
(in article <09.185.53134.PUA.250.501.RemoveThis@amhuinnsuidhe.net>):

>
>
> On 2009.07.04 07:34:25,
> the amazing <kevinmcm.RemoveThis@sonic.net> declared:
>
> <snip!>
>
>> Linksys router, NAT, and firewall solutions are pathetic. No features,
>> no throughput, and very prone to crashing. I don't think you'll find a
>> better solution than ditching it.
>
> I've been using a Linksys BEFSR for quite a while, and
> it seems to do the job OK. On the BEFSR you specify what
> IP range you let the DHCP server control. I only let it
> control a small number, so guests can plug into the net.
> Our two Apples, and our backup drive, claim their own IPs.
>
> But obviously my notion that the Linksys does everything
> I expect a router to do doesn't have much grounding, since
> the only router I've ever had is a Linksys Eventually
> I'll have to replace it. Is there consensus about which
> brands are good? Maybe I should ask whether there's a web
> site that has ratings....

The best consumer router is Apple's Airport Extreme. It does everything:
DHCP, NAT, easily sets DHCP pools, easily reserves IPs, can create multiple
networks if necessary, knows both IPv4 and IPv6, knows many varieties of WPA
(and WEP, which is useless...) and does _NOT_ use a HTML page for
configuration, and so is hard to hack remotely. It also doesn't use stupid
passwords as defaults.

The best business routers depend on what you want to do and what your budget
is. Low-end business routers start at $1000. Good ones cost more.


--
email to oshea dot j dot j at gmail dot com.

In article <h2nqhj01653.TakeThisOut@news1.newsguy.com>,
J.J. O'Shea <try.not.to.TakeThisOut@but.see.sig> wrote:

> The best consumer router is Apple's Airport Extreme. It does everything:
> DHCP, NAT, easily sets DHCP pools, easily reserves IPs, can create multiple
> networks if necessary, knows both IPv4 and IPv6, knows many varieties of WPA
> (and WEP, which is useless...) and does _NOT_ use a HTML page for
> configuration, and so is hard to hack remotely. It also doesn't use stupid
> passwords as defaults.

My DGL 4300 does all that, and yeah, it has an HTML setup page, I
wouldn't have it any other way; it's very secure if it's used correctly.
Passwords are the responsibility of the user, not the vendor. If the
user is too stupid to change the default, then he's probably too stupid
to tie his shoe laces as well.

And the Airport is anything but "Extreme," at least as a receiver. The
only laptops that don't pick up the signal at the back of the house are
Apple laptops.
--
Suddenly he realized that he was alone
with a giant halfwit on a dark deserted street.
-- Chester Himes

In article <h2ngj412aam.DeleteThis@news7.newsguy.com>,
J.J. O'Shea <try.not.to.DeleteThis@but.see.sig> wrote:

> On Sat, 4 Jul 2009 02:00:30 -0400, Barry Margolin wrote
> (in article <barmar-DA6257.02003004072009.DeleteThis@news.eternal-september.org>):
>
> > In article <h2movb036c.DeleteThis@news6.newsguy.com>,
> > J.J. O'Shea <try.not.to.DeleteThis@but.see.sig> wrote:
> >
> >> On Fri, 3 Jul 2009 23:09:07 -0400, Gene E. Bloch wrote
> >> (in article <wizyxh36qmpl.1mggm4zi65arb$.dlg@40tude.net>):
> >>
> >>> On Fri, 03 Jul 2009 13:27:46 -0700, YA MacUser wrote:
> >>>
> >>>> Greetings and thanks for reading this.
> >>>> With D-Link consumer routers, it is easy to have the DHCP server always
> >>>> assign the same LAN address to a given MAC number so port forwarding
> >>>> will go to the computer with that LAN address.
> >>>> I need to do this to a Linksys WRT54G router but can't find a
> >>>> recognizable page in the setup. Where to control the DHCP server?
> >>>> Kind regards
> >>>
> >>> Can't you tell the computer with that MAC address to use a fixed IP
> >>> address?
> >>>
> >>> That's the way it works in Windows (and it's easy to do).
> >>>
> >>>
> >>
> >> If he uses a fixed IP that's within the DHCP pool, the router might
> >> allocate
> >> that IP to something else. That would be bad. Most routers allow for IPs
> >> to
> >> be reserved for particular MAC addresses. The Linksys User Guide details
> >> how.
> >> Chapter 8, IIRC.
> >
> > So he should use a fixed IP that's NOT within the DHCP pool.
>
> Yes. IIRC Linksys routers usually set the DHCP pool to be from 192.168.1.10
> on up to 192.168.1.254. The router itself is usually 192.168.1.1, and of
> course 192.168.1.0 and 192.168.1.255 can't be used, so that leaves
> 192.168.1.2 to 192.168.1.9 available for use.

It's been a while since I initially set mine up, so I could be
remembering incorrectly, but I think the default range starts at .100,
not .10. But even if not, it's simple to change the range it uses, if
you need more fixed addresses.

The problem with configuring a static IP, though, is that you also have
to configure DNS statically. It would be preferable to get the ISP's
DNS from the router via DHCP. Apple has an option in the Network
preference for "Using DHCP with manual address", but this doesn't seem
to work with Linksys routers. We had a thread a couple of years ago
about this.

>
> >
> > I have a WRT54G, and AFAIK it doesn't have a way to configure static
> > MAC->IP mappings for the DHCP server. Maybe this can be added with
> > DD-WRT firmware.
>
> I could be wrong about this, but I'd be surprised if I were as that would
> make Linksys the only vendor which doesn't support reserved IPs, which is a
> standard TCP feature. Certainly the routers I have at home and at the office
> support reserved IPs. I use them all the time for printers, servers, NAS
> boxes, and laptops.

I'm practically certain I'm correct. This isn't a "standard TCP
feature", it's a configuration option in some (perhaps most) DHCP
servers. It doesn't affect the wire protocol, so it's not something
that needs to be standardized across implementations.

--
Barry Margolin, barmar.DeleteThis@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***
*** PLEASE don't copy me on replies, I'll read them in the group ***

J.J. O'Shea wrote:

> The best consumer router is Apple's Airport Extreme.
....
> and does _NOT_ use a HTML page for configuration

There's something I really *hate* about the Airport, namely that I need
a special app to cofigure it.

On Sat, 4 Jul 2009 12:45:41 -0400, Barry Margolin wrote
(in article <barmar-2CA4AF.12454104072009 RemoveThis @news.eternal-september.org>):

> In article <h2ngj412aam RemoveThis @news7.newsguy.com>,
> J.J. O'Shea <try.not.to RemoveThis @but.see.sig> wrote:
>
>> On Sat, 4 Jul 2009 02:00:30 -0400, Barry Margolin wrote
>> (in article <barmar-DA6257.02003004072009 RemoveThis @news.eternal-september.org>):
>>
>>> In article <h2movb036c RemoveThis @news6.newsguy.com>,
>>> J.J. O'Shea <try.not.to RemoveThis @but.see.sig> wrote:
>>>
>>>> On Fri, 3 Jul 2009 23:09:07 -0400, Gene E. Bloch wrote
>>>> (in article <wizyxh36qmpl.1mggm4zi65arb$.dlg@40tude.net>):
>>>>
>>>>> On Fri, 03 Jul 2009 13:27:46 -0700, YA MacUser wrote:
>>>>>
>>>>>> Greetings and thanks for reading this.
>>>>>> With D-Link consumer routers, it is easy to have the DHCP server always
>>>>>> assign the same LAN address to a given MAC number so port forwarding
>>>>>> will go to the computer with that LAN address.
>>>>>> I need to do this to a Linksys WRT54G router but can't find a
>>>>>> recognizable page in the setup. Where to control the DHCP server?
>>>>>> Kind regards
>>>>>
>>>>> Can't you tell the computer with that MAC address to use a fixed IP
>>>>> address?
>>>>>
>>>>> That's the way it works in Windows (and it's easy to do).
>>>>>
>>>>>
>>>>
>>>> If he uses a fixed IP that's within the DHCP pool, the router might
>>>> allocate
>>>> that IP to something else. That would be bad. Most routers allow for IPs
>>>> to
>>>> be reserved for particular MAC addresses. The Linksys User Guide details
>>>> how.
>>>> Chapter 8, IIRC.
>>>
>>> So he should use a fixed IP that's NOT within the DHCP pool.
>>
>> Yes. IIRC Linksys routers usually set the DHCP pool to be from 192.168.1.10
>> on up to 192.168.1.254. The router itself is usually 192.168.1.1, and of
>> course 192.168.1.0 and 192.168.1.255 can't be used, so that leaves
>> 192.168.1.2 to 192.168.1.9 available for use.
>
> It's been a while since I initially set mine up, so I could be
> remembering incorrectly, but I think the default range starts at .100,
> not .10. But even if not, it's simple to change the range it uses, if
> you need more fixed addresses.

You could easily be right, it's been a long time since I played with a
Linksys.

>
> The problem with configuring a static IP, though, is that you also have
> to configure DNS statically. It would be preferable to get the ISP's
> DNS from the router via DHCP. Apple has an option in the Network
> preference for "Using DHCP with manual address", but this doesn't seem
> to work with Linksys routers. We had a thread a couple of years ago
> about this.

I always put in a DNS server anyway. Usually OpenDNS.

>
>>
>>>
>>> I have a WRT54G, and AFAIK it doesn't have a way to configure static
>>> MAC->IP mappings for the DHCP server. Maybe this can be added with
>>> DD-WRT firmware.
>>
>> I could be wrong about this, but I'd be surprised if I were as that would
>> make Linksys the only vendor which doesn't support reserved IPs, which is a
>> standard TCP feature. Certainly the routers I have at home and at the
>> office
>> support reserved IPs. I use them all the time for printers, servers, NAS
>> boxes, and laptops.
>
> I'm practically certain I'm correct. This isn't a "standard TCP
> feature", it's a configuration option in some (perhaps most) DHCP
> servers. It doesn't affect the wire protocol, so it's not something
> that needs to be standardized across implementations.
>
>

I stand corrected.


--
email to oshea dot j dot j at gmail dot com.

Greetings and many thanks for your comments from which, I take it that
the Linksys WRT54G is not capable of having its DHCP server reserve IPs
for given MAC addresses.
Kind regards

--
---------------------------------

In article <040720091515562438%nospam@home.com>, YA MacUser
<nospam.RemoveThis@home.com> wrote:

> Greetings and many thanks for your comments from which, I take it that
> the Linksys WRT54G is not capable of having its DHCP server reserve IPs
> for given MAC addresses.

it very definitely is if you use third party firmware.