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Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

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Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#61

Post by pnopnopno »

taurath wrote: post #14
lathiat wrote: post #5

Interesting nugget of information here: > Thanks to Steinar H. Gunderson for pointing out in the comments that the DHCP server on my test network was incorrectly configured. Since I was using a mostly "out of the box" dhcpd configuration from Ubunbtu Linux, it wasn't set up to be authoritative by default, so it wasn't promptly sending NAKs in response to the Galaxy Tab's requests for an old IP address. After fixing t…

An instruction like that is why I don't use Linux as a desktop!

You should try disabling mouse acceleration using your mouse, that's even better. Setting server stuff is one thing, but it's ridiculous that using a mouse is not considered important enough for simple users to be able to customize.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#62

Post by ntnn »

taurath wrote: post #14
lathiat wrote: post #5

Interesting nugget of information here: > Thanks to Steinar H. Gunderson for pointing out in the comments that the DHCP server on my test network was incorrectly configured. Since I was using a mostly "out of the box" dhcpd configuration from Ubunbtu Linux, it wasn't set up to be authoritative by default, so it wasn't promptly sending NAKs in response to the Galaxy Tab's requests for an old IP address. After fixing t…

An instruction like that is why I don't use Linux as a desktop!

> An instruction like that is why I don't use Linux as a desktop!

This has nothing to do with the linux desktop - this is a misconfiguration of the dhcp server, which would affect all clients. The mac circumvented the issue because it sends out information of all previous networks (which is a security issue, btw - I'd rather not want my laptop to push out all of my recent networks' information to anybody).

Also, this guy is running his own ISC dhcpd server to have more control over the network and to learn more about networking in general. This is not a professional network admin/dev - of course he doesn't do all of it right, but if he'd read the manual, he would've enabled it. Seriously, even in default configurations the option is marked as 'if this is the only DHCP server in the network you'll want to enable this' or something along the lines of that.

So we're not speaking about an out-of-the-box ready-to-roll router - we're talking about a guy who's running a server with Ubuntu on it to provide leases to his network.

Besides - the same would've happened if a windows user were to use Microsoft's DHCP server, which is non-authoritative by default as well. It's a good practice that a DHCP server on default configuration doesn't assume to have the authority - since, well, since the configuration has not been touched.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#63

Post by pjmlp »

pjc50 wrote: post #59
pjmlp wrote: post #54

Earlier quoted context omitted.

I am familiar with Windows since version 3.0 and was introduced to UNIX via Xenix. As for GNU/Linux, I know it since Slackware 2.0.

I thought you'd be familiar with it; I was talking about third parties who might not be familiar with either.

If they aren't familiar with either, the amount of documentation in Technet and wizards help, is much better than searching man pages.

Leaving aside the fact that the variation among Windows versions is quite small versus the GNU/Linux distribution fragmentation.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#64

Post by ntnn »

pilif wrote: post #52
herbst wrote: post #42

Earlier quoted context omitted.

The windows equivalent to make such a change would be some kind of hidden module for that scm. Exe or whatever that obscure config tool is called.

In this specific case, the DHCP server configuration under Windows makes it abundantly clear though that you need to make your DHCP server authoritative by adding a warning icon and presenting a warning dialog when it's not running in authoritative mode. Making it authoritative is then to just press a button in that dialog. Yes. You have to know that you have to open the GUI for DHCP server configuration in order to…

From when and which distro is that default config file? I remember having a text next to it saying 'Enable this, if this is the only DHCP server on this network' or something along the lines of that with a pointer to the documentation for an explanation.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#65

Post by 3pt14159 »

kalleboo wrote: post #10

I remember this feature used to cause a lot of problems with random IP conflicts, but I haven't had an IP conflict like that in years, so it seems they've made it a lot more robust. Or are routers/DHCP servers just less broken these days (I guess since Apple's market share has forced them to)?

It still happens. I run Ubuntu on a MBP (dual boot) and some networks are fucking great. No problems whatsoever. Others I get booted off more frequently the more people enter the cafe. I dug into the problem a while back and figured out it was this shitty behaviour by Apple that Ubuntu hadn't fixed.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#66

Post by tolien »

ntnn wrote: post #64
pilif wrote: post #52

Earlier quoted context omitted.

In this specific case, the DHCP server configuration under Windows makes it abundantly clear though that you need to make your DHCP server authoritative by adding a warning icon and presenting a warning dialog when it's not running in authoritative mode. Making it authoritative is then to just press a button in that dialog. Yes. You have to know that you have to open the GUI for DHCP server configuration in order to…

From when and which distro is that default config file? I remember having a text next to it saying 'Enable this, if this is the only DHCP server on this network' or something along the lines of that with a pointer to the documentation for an explanation.

The current isc-dhcp-server package in Debian testing has that comment, although there’s a line missing…

  # If this DHCP server is the official DHCP server for the local
  # network, the authoritative directive should be uncommented.
From that, it’s a little more clear that you should be uncommenting that option.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#67

Post by KekDemaga »

Nition wrote: post #19
taurath wrote: post #14

Earlier quoted context omitted.

An instruction like that is why I don't use Linux as a desktop!

I'm a bit disappointed that you're downvoted to grey right now because editing obscure config files and entering esoteric terminal commands is exactly why Linux is so difficult for the average user, and it's never going to improve if those who're already comfortable with it ignore the problem.

I say the same thing about the space shuttle, it should have one button "go to space".

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#68

Post by geocar »

ntnn wrote: post #62
taurath wrote: post #14

Earlier quoted context omitted.

An instruction like that is why I don't use Linux as a desktop!

> An instruction like that is why I don't use Linux as a desktop! This has nothing to do with the linux desktop - this is a misconfiguration of the dhcp server, which would affect all clients. The mac circumvented the issue because it sends out information of all previous networks (which is a security issue, btw - I'd rather not want my laptop to push out all of my recent networks' information to anybody). Also, this…

> The mac circumvented the issue because it sends out information of all previous networks ... I'd rather not want my laptop to push out all of my recent networks' information to anybody

It's some information about the last few _wired_ networks you've connected to, to any of those networks, that the owners of those networks already have. If you have a wifi you already know which network you're on, and there's no sense in asking about addresses you haven't seen with that SSID+key.

There certainly appears to be a privacy issue if you're connecting to a lot of public ethernets and those sites (can) collude, however if those sites can and do work together, they can unmask you anyway.

If they don't yet collude (but are willing) and you don't use random MAC addresses, then there may be another privacy issue where they can use the MAC address you leak to discover each-other, but I'm unconvinced even Google has the resources to do this.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#69

Post by kalleboo »

mdekkers wrote: post #26
ams6110 wrote: post #3

Could have been titled: How do Apple devices wreak havoc on home networks. When my kid comes home with his iPhone there is a better than even chance that my home network will go out to lunch. Router reboot time. Never happens with Windows or Android devices coming and going.

My SO unfortunately has 2 ipones, an ipad and a MBP. There is a confluence of DHCP activity from all these devices that is guaranteed to take my network down.

Our home network has 6+ Apple devices and a pile of other stuff (Smart TVs, DVRs, game consoles, media converters, etc) and it has zero problems whatsoever. Our router is some generic thing by NEC that I bought off the shelf at a big-box retailer because it had the biggest numbers on the box.

Re: Rapid DHCP: Or, how do Macs get on the network so fast? (2011)

#70

Post by dspillett »

pilif wrote: post #52
herbst wrote: post #42

Earlier quoted context omitted.

The windows equivalent to make such a change would be some kind of hidden module for that scm. Exe or whatever that obscure config tool is called.

In this specific case, the DHCP server configuration under Windows makes it abundantly clear though that you need to make your DHCP server authoritative by adding a warning icon and presenting a warning dialog when it's not running in authoritative mode. Making it authoritative is then to just press a button in that dialog. Yes. You have to know that you have to open the GUI for DHCP server configuration in order to…

> the DHCP server configuration under Windows

Though for the opening to the current discussion that is a moot point - this is not relevant to either OS on the desktop.

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