An incorrect IP address is returned (nslookup)

[blackcat4866]

Now David you been around long enough to understand most of it.

I'm aware of the existence of Bios & NetBios, but I'm not real clear on what it does. I know I can boot my laptop into Bios mode to make such settings ... that's about it. If I were to make a guess I'd say Bios is a more basic version of the computer operating system that boots before Windows.

I've used hostnames and IP's before ... even came across identical hostnames before.

My first inclination on Billy's question was that the hostname had a specific IP reserved on the router, and the IP of the computer had been changed. Is that a possibility?

[PrintWhisperer]

I'm aware of the existence of Bios & NetBios, but I'm not real clear on what it does....

Yes, BIOS we know as the Basic Input Output System for your hardware.

NetBIOS is a network protocol to govern the basic input/output sessions on and over networks. (Primarily during the Pre-internet peer to peer serverless environments...remember dial-up?)

It's old, insecure, and best turned OFF, always.

I used the wireshark sample just to show how the initial connection is handled differently in the NetBIOS only world, this photo is marked up with some more notes on what is going on.
1) The MFP initiates a session (OSI Layer 5) and needs the IP address of the 'scan-to' computer.
2) The IP address is provided.
3) ARP sets up the Data Link (Layer 2)
4) The session proceeds to connect the MFP to Transport over TCP (Layer 3) destined for service on port 139

NBNS.jpg

The rest of this capture has the host attempting to change to port 445 for domain auth but cannot and fails.

But that's another discussion

[rthonpm]

I'll be the first to admit that I'm mostly ignorant when it comes to NetBios Name Resolution. I'm gonna make it a point to learn it this weekend.

NetBIOS and WINS were the resolution protocol before DNS. In modern environments there's no reason to have them enabled as they're essentially dead. The only reason you'd need it enabled is if you somehow have something older than Windows NT on your network, and if you're connecting something that old, you definitely have other issues...

It was also part of the reason that SMB 2 changed from port 139 to 445. Port 139 is SMB over WINS, while 445 is SMB over DNS. SMB 2 was more of a re-write than an update.


Unfortunately there's no real way to force a DNS flush on the MFP. The closest thing you can do is to change the IP for the DNS Server on the MFP, reboot, then change it back to the real value.

I haven't been a big fan of ISP equipment handling anything for the LAN side in years. Often, they'll offer their external DNS servers as the internal ones, which kills any attempt at local name resolution. I've been down that road before, as well as customers using Google or some other public DNS and wondering why they can't talk to local devices.

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[BillyCarpenter]

Man, there's a lot of good information in this thread. Even though scan to folder is working after I used the IP address instead of hostname, I think I'll go back and try some of the suggestions in this thead. I'm only doing this because I hate not doing a job the right way. I feel like I used a bandaid by using the IP address.


On another note: Do you guys do this type of stuff free or do you charge? This isn't covered under my service contract. (I'm not gonna charge them but I'm just curious)

[BillyCarpenter]

Unfortunately there's no real way to force a DNS flush on the MFP. The closest thing you can do is to change the IP for the DNS Server on the MFP, reboot, then change it back to the real value.


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I just made a note of that. Thank you very much.

[rthonpm]

On another note: Do you guys do this type of stuff free or do you charge? This isn't covered under my service contract. (I'm not gonna charge them but I'm just curious)

For me, if it's a network support customer, then it's covered. For printer customers, I'll do a first look to make sure it's not an MFP issue and then punt it to their IT with any findings. For a time and materials customer, it's charged under my consulting fee, which is less than my labour charge, but it's a two hour minimum rate.

There are a couple of customers that I may throw something at for free, but they've got to be a really long standing customer; or at least too far out to drive to, depending on what else is going on.

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[PrintWhisperer]

I've had this problem before, even posted about it. I'll have to disable NetBIOS over TCP/IP to see if I'm able to get those copiers scanning using the host name instead of the ip.

Fair warning you can lose some features that use NetBIOS sessions where the machine acts like a host sharing a printer or folder (Printing to \\MFP\Printer UNC connection). It doesn't affect TCP/IP port printing.

NetBIOS and WINS were the resolution protocol before DNS...

All correct but it is important to point out that WINS is a service running on a Server to centralize name tables. Lacking a server (configured WINS address) NBNS takes over with a broadcast which is only to the local subnet.

I remember having a chart on the wall back in the day of the WINS name resolution loop, but this is as close as I could find:
netbios-over-tcpip.jpg

[Hansoon]

Unfortunately most of it passes way over my head.

Phew, and I thought being the only one here....
Very interesting thread though. Thanks guys.

BTW: What's so bad of giving the MFP a static IP-Address?

Hans

[BillyCarpenter]

BTW: What's so bad of giving the MFP a static IP-Address?

Hans

There's nothing wrong with giving the MFP a static address. That's what I always do. You never want it to have a DHCP. Use either static or reserve the IP address via DHCP.

[Hansoon]

Use either static or reserve the IP address via DHCP.

Yep, that's what I'm doing since years too without exception. If possible, a static IP and at least a hardware reservation for it in the router.

Got a moment somehow the wrong impression here that a static IP would be less desirable.

Hans