How to check IP address at startup?

[Galen Tackett]

My OS X 10.1.5 sometimes gets an incorrect IP from the DHCP on my DI-604
router. In binary, the address looks sort of, but not quite, like a
correct address that has been bit-shifted--a few bits (not at the
shift-in end of the address) don't match as well.

Is there a way I could have an AppleScript script examine the IP address
and make sure that the three leftmost bytes of the address are correct?

Galen

--
Galen Tackett

*** To e-mail me just remove the spam from my address

[Tom Stiller]

In article
<gspamtackett-FFEF97.16513208102003@news.comcast.giganews.com>,
Galen Tackett <gspamtackett@yahoo.com> wrote:

> My OS X 10.1.5 sometimes gets an incorrect IP from the DHCP on my DI-604
> router. In binary, the address looks sort of, but not quite, like a
> correct address that has been bit-shifted--a few bits (not at the
> shift-in end of the address) don't match as well.
>
> Is there a way I could have an AppleScript script examine the IP address
> and make sure that the three leftmost bytes of the address are correct?
>
> Galen

What does the address look like in dotted decimal notation? If it
starts with '169' it probably indicates that the DHCP server isn't
supplying an address and the OS is generating one for use in a strictly
local LAN.

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF

[Hugh Wolf]

On 2003-10-08, Galen Tackett <gspamtackett@yahoo.com> wrote:

> My OS X 10.1.5 sometimes gets an incorrect IP from the DHCP on my DI-604
> router. In binary, the address looks sort of, but not quite, like a
> correct address that has been bit-shifted--a few bits (not at the
> shift-in end of the address) don't match as well.

Sounds very suspicious.

> Is there a way I could have an AppleScript script examine the IP address

It's easy with a shell script. One way would be:

ifconfig en0 | grep inet | awk '{print $2}'

assuming the default ethernet interface. This will give you the
address in standard dotted form: a.b.c.d.

[Hugh Wolf]

On 2003-10-09, Hugh Wolf <hwolf@deutsches.lieder.de> wrote:

> ifconfig en0 | grep inet | awk '{print $2}'

Even easier: ipconfig getifaddr en0

[Galen Tackett]

In article
<tomstiller-57A690.17434708102003@news.comcast.giganews.com>,
Tom Stiller <tomstiller@comcast.net> wrote:

> In article
> <gspamtackett-FFEF97.16513208102003@news.comcast.giganews.com>,
> Galen Tackett <gspamtackett@yahoo.com> wrote:
>

> > My OS X 10.1.5 sometimes gets an incorrect IP from the DHCP on my DI-604
> > router. In binary, the address looks sort of, but not quite, like a
> > correct address that has been bit-shifted--a few bits (not at the
> > shift-in end of the address) don't match as well.
> >
> > Is there a way I could have an AppleScript script examine the IP address
> > and make sure that the three leftmost bytes of the address are correct?
> >
> > Galen

>
> What does the address look like in dotted decimal notation? If it
> starts with '169' it probably indicates that the DHCP server isn't
> supplying an address and the OS is generating one for use in a strictly
> local LAN.

You hit the nail on the head, Tom. Thanks for the information!

Thanks, also, Hugh, for your help.

And the next question is (if you care to take it on):

The DI604 log shows it assigning an address to my Mac. Why might the Mac
not see it? (This is merely intermittent so it's hard to use something
like tcpdump to watch what's happening.)

My home network runs on Siemens SpeedStream HomePlug and apart from this
has been extremely reliable and fast.

Thanks again!

--
Galen Tackett

*** To e-mail me just remove the spam from my address

[Tom Stiller]

In article
<gspamtackett-E607E4.17002109102003@news.comcast.giganews.com>,
Galen Tackett <gspamtackett@yahoo.com> wrote:

> In article
> <tomstiller-57A690.17434708102003@news.comcast.giganews.com>,
> Tom Stiller <tomstiller@comcast.net> wrote:
>

> > In article
> > <gspamtackett-FFEF97.16513208102003@news.comcast.giganews.com>,
> > Galen Tackett <gspamtackett@yahoo.com> wrote:
> >

> > > My OS X 10.1.5 sometimes gets an incorrect IP from the DHCP on my DI-604
> > > router. In binary, the address looks sort of, but not quite, like a
> > > correct address that has been bit-shifted--a few bits (not at the
> > > shift-in end of the address) don't match as well.
> > >
> > > Is there a way I could have an AppleScript script examine the IP address
> > > and make sure that the three leftmost bytes of the address are correct?
> > >
> > > Galen

> >
> > What does the address look like in dotted decimal notation? If it
> > starts with '169' it probably indicates that the DHCP server isn't
> > supplying an address and the OS is generating one for use in a strictly
> > local LAN.

>
> You hit the nail on the head, Tom. Thanks for the information!
>
> Thanks, also, Hugh, for your help.
>
> And the next question is (if you care to take it on):
>
> The log shows it assigning an address to my Mac. Why might the Mac
> not see it? (This is merely intermittent so it's hard to use something
> like tcpdump to watch what's happening.)
>
> My home network runs on Siemens SpeedStream HomePlug and apart from this
> has been extremely reliable and fast.
>

I can't ay for sure, but my guess would be that the DI604 isn't
responding before the Mac gives up. Depending on the model of Mac
and/or router characteristics, there may be too much time lost
negotiating the link speed.

I moved up to Jaguar as soon as it was released and so, don't have
anything running 10.1.x to experiment with :-(

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF