Network hard disk stuff again

[ffutures]

I've been asked for more details - since I don't think the network disk is accessible from outside I might as well post them for everyone:



It's a no-name network hard disk housing, containing a 350gb hard disk
Host name = "Hermione"
Group name = "Aeronef"

IP - 192.168.0.6
Subnet - 255.255.255.0
Gateway - 192.168.0.1
Primary DNS - 192.168.0.1
DHCPS - Auto
IP pool starting IP - 2
IP pool ending IP - 253

The network status thingy in the iBook says

configure IPv4 using DHCP
IP Address: 192.168.0.101
Subnet mask: 255.255.255.0
Router: 192.168.0.1

I've tried running network diagnostics but it says everything's OK.



To reiterate, I can connect to the internet and to a network printer, and my other computers can connect to Hermione, but suddenly the iBook can't.

Any suggestions?

Comments

[ffutures.livejournal.com]

Sorry, my ignorance is showing here - why would I want it to have an address outside my network? Wouldn't that make it inaccessible?

192.168.0.1 is the router address. I can only assume that for some reason the hard disk has a record of the address.

[turol.livejournal.com]

That's your DNS server. It's used to map domain names to IP addresses. Most people use their ISP's server. Your ADSL box is telling the network to use it as DNS and then just forwards the requests to your ISP. This way changes to your ISP's configuration are transparent to the internal network.

It's possible to use any DNS server which agrees to process your queries. Most don't, but Google runs publicly accessible servers at some well-known addresses. In this scenario using those doesn't gain you anything.

[nojay.livejournal.com]

The network HD has a DNS entry in its configuration setup and at the moment it's pointing directly at Marcus' gateway/router (192.168.0.1). It's possible the gateway would transparently proxy any DNS requests to whatever DNS server its ISP has set it up with but if it isn't doing that then when/if the network HD tries to resolve a domain name then it will fail.

All the PCs on our home network have explicit external WAN DNS addresses (in our case, two servers belonging to Demon's at 158.152.1.x). When domain name service is requested the gateway will pass the relevant request out onto the WAN to Demon's DNS server and the PC gets an IP address back. I just suggested the Google server at 8.8.8.8 as it is public and reliable.

What DNS is the iBook using? I didn't see that mentioned in Marcus' original posting. If he's not getting proper DNS service then he's not going to get very far on the internet. What sort of ping tools are available on OS/X?

[turol.livejournal.com]

> It's possible the gateway would transparently proxy any DNS requests to
> whatever DNS server its ISP has set it up with but if it isn't doing that
> then when/if the network HD tries to resolve a domain name then it will
> fail.

Well since he's posting here it presumably works...

[nojay.livejournal.com]

That's the iBook he's using to post, I think. The network HD has a DNS server address setting which means it, for some reason, might want to resolve domain names and needs to know the address where it can find a DNS server. At the moment it's pointing to the gateway, not a real DNS server. That's what is puzzling me.

Thinking about this the DNS thing is probably not what is causing the problem of the iBook not seeing the HD or vice-versa, it just caught my eye and it's easy to fix, just set the DNS value in the HD's control panel to point to a real server on the WAN.

I suspect the HD can't see the iBook, possibly because its DHCP server thinks it issued an IP address to the iBook (something like 192.168.0.3) and it didn't in fact do this as something else had previously issued the address 192.168.0.101. Having more than one DHCP server on a LAN segment is usually OK but badly-written and insufficiently-tested firmware can screw up in this regard if more than one DHCP server thinks it is definitive.

I assume the iBook and the HD are plugged into the network switch which is usually part of the ADSL/cable modem? Another classic fail is when the switch's routing table messes up and prevents access to some address or other. A hard power/cycling reset of the router usually fixes that problem (until the next time it happens).

[ffutures.livejournal.com]

No, I'm using wifi for the ibook. I've tried resetting it, doesn't seem to help. I've just tried a wired connection instead, that also works fine for the internet and printing, but not for the network hard disk.

[ffutures.livejournal.com]

There's a ping as part of the network utility. If I ping Hermione it can't find it

ping: Cannot resolve hermione: unknown host

I don't know how to find the DNS information for the ibook.

As I said, usually I just mount the drive as a network drive on the iBook - until a couple of days ago I haven't had problems, and I haven't changed anything in the network configuration at all.

[nojay.livejournal.com]

Did you ping "Hermione" or "192.168.0.6"? Try pinging the naked IP address of the HD and see what comes back.

[ffutures.livejournal.com]

Pinging 192.168.0.6 gives 10 packets transmitted, 10 packets received, 0% packet losss
round trip min/avg/max/stddev - 1.612/3.498/14.325/3.720ms

Looking at the list the first was the long one, after that they were mostly under 2ms

[nojay.livejournal.com]

That shows there is IP connectivity between the iBook and the hard disk. The problem is occurring at a higher protocol level and I can't really help you with that, not at this distance. Sorry.

[turol.livejournal.com]

> I don't know how to find the DNS information for the ibook.

Linux and most Unix-like systems put it in /etc/resolv.conf

Don't know if this works on OS X, /etc might be called /Etc or something.

[ffutures.livejournal.com]

Can't find anything like that but I may be looking in the wrong place.