What is wrong with NowTV IP address?

[johric]

I'm having another go at fixing a long standing irritating problem with NowTV if anyone can please help with possible solutions to try? Or even an explanation of what might be going on?

50% of the time when I start my computer (recent Mac running very latest software) it does not connect to the internet. Once this has happened no amount of waiting makes any difference and I have to restart the computer to connect. Network settings tell me ethernet connected OK but either "computer does not have an IP address" or has "self-assigned IP address and will not be able to connect".

Apple Support say the problem is with the ISP, NowTV say it is with Apple but have provided a new router anyway.

Is there anything I can do? Should I (can I, even) change servers? Or should I just live with it? (Once initially connected broadband is full speed and stable).

[Jayach]

Do you have other devices that are able to get I.P. addresses without problem?

Have you anything on the network that may be clashing with the DHCP server?

From what you say, you are using Ethernet, so next time it happens disconnect the Ethernet cable and reconnect it, and see if it then gets an I.P. address.

[johric]

Thanks – I don't really use other devices, but visitors not reported any problems. At least 50% of the time my own computer does not exhibit any problem either. I don't have anything else on the network – what sort of thing might be clashing?

I can disconnect ethernet, restart or re-set router and yes then the connection would be OK, but as far as I'm aware this would only be a random fix, in the same way that restarting the computer would be i.e. it would probably work OK then but is not a permanent fix. I would have to repeat the process dozens of times to see if it had any real effect more than random chance, if you see what I mean?

So it's easier and faster to restart the computer.

Once the connection is rejected it stays rejected until I do one of the above and I can't understand why if the computer is looking for a server it doesn't just carry on trying until it finds it?

[Jayach]

On your other thread, you were thinking of using an old Now router as an access point,

If you did that with a Now router (or any other router), but didn't disable the DHCP in it that would cause exactly what you describe, as occasionally it would hand out an IP address, but with itself as the gateway and it has no connection to the net.

[Jayach]

Darn, wanted to edit the above, but we can't anymore.

It wouldn't cause exactly what you describe, as you say the PC doesn't get an IP, but 2 DHCP servers could still be the problem. 

[johric]

Thanks Jayach, but no this was happening long before my previous thread. The additional router works great but is actually switched off 99% of the time anyway.

[Jayach]

The problem is obviously DHCP related. For some reason the Mac isn't getting an IP address from the server in the Now router. Whether that is a problem with either device or something else that may be interfering with the normal working (like a second DHCP server somewhere) is hard to determine.

[johric]

I know nothing about DHCP but my thinking is that if it was the NowTV router I have had a new one so that should be OK; and if it was the NowTV service then there would be a lot more complaints about this issue on the community support pages, which I don't see? So that leads me to computer settings, but they don't get changed between successful and unsuccessful log-ins. And anyway, shouldn't the computer keep trying to connect until successful and send an error message if not? But it just tries once then does nothing which seems to me is not very Mac-like behaviour? I need some sort of logarithm of things to try to work through but as the fault is intermittent I wouldn't really know if they had worked or not for a long time.

[Jayach]

DHCP(Dynamic Host Configuration Protocol) is the method by which devices get their I.P. from the router.

If a DHCP request doesn't get an reply, it is usual for the device to give itself an Auto configuration IPv4 address. (which I believe you are seeing)

That would suggest a way you could resolve the problem, give the Mac a static address.

I don't use a Mac but this may point you in the right direction:

Static IP for Mac OS X | Information Management Systems and Services (caltech.edu)

[RoyB]

@johric 

I recommend you download the free Fing for Desktop, Mac version, and let it sniff your network.

The Windows version was excellent for sniffing my network, and discovering an unexpected duplicate DHCP server (in a device which I thought, and still think, had no business running one!), which I was then able to turn off.

Fing reserves a few features for its paid version, which it encourages you to subscribe to, but I have been able to resist its blandishments and do pretty much everything I have needed with the free version.