Thread
DHCP & Configuring Subnets
Need help! I have a friend going to Law School in the DC area. Judging by his email, I think he needs a way to configure a subnet mask WHILE using DHCP. I gather the law school has segmented it's IP range in such a way the OS X netowrking GUI may not be able to handle.
He's a novice. However, this question has passed my knowledge of networking. Can you please read his email and ponder a solution for our good friend, Rich?
-SM
------
>Date: Thu, 19 Sep 2002 21:05:37 -0400
>
>Chris,
>
>Ellen Feiss is the whole reason I got my mac. She's kinda hot in
>that "she's-a-high-college-girl" kind of way. There are whole
>websites dedicated to her. I think you can even get an OSX icon
>with her picture...
>
>Also: Here's my best shot at explaining my network story. If you
>have any ideas, I'm all ears, but it sounds like the CUA-Law network
>is just wired in a way that did NOT anticipate supporting Macs.
>Read it if you're interested from a techincal standpoint, for sheer
>entertainment. Otherwise, have a great day and don't let let the
>thought that I spent 1/2 the night trying to write this all out even
>cross your mind. ;-)
>
>I talked with CUA-Law's network guy. He explained that 1. The law
>school network runs as a sub-branch of the university network (keep
>the distinction in mind as you read on), and 2. on the CUA network,
>the gateway and the stream come in on 2 different DHCP addresses (?)
>or subnet masks or whatever (that allows them to separate students
>from admin., for network security). On Windows 2000, they just
>manually change the setting, but OSX.1 assumes the gateway and
>stream come in on the same... thing.
>
>I hooked up my G4 (looking all cool, flashing my titanium and
>whatnot)and showed him that I was sending (some) ping and receiving
>(lots of) ping. The little ethernet light was going "blink blink
>blink." Obviously, we were getting a feed.
>
>We played with the apple talk "on" button and managed to get the
>connection up... in his office. He thinks were were piggy-backing
>on the university network's appletalk zone. The catch is, the law
>school is wired a little differently.
>
>The problem on the law school network is that every other network
>connection that students can access goes through a switch that
>doesn't have the appletalk zone turned on.
>
>Anyway, I left him scratching his head trying to figure this problem
>out. I don't know how the CUA network compares to most systems, but
>it seems like they should just enable the appletalk zone on the
>switch machine and voila! He said that would take some programming,
>and there's only one guy on campus certified to do that, so it would
>take about... 10 years.
>
>Anyway, all is not lost. They're piloting a wireless network, which
>happens NOT to go through this mac-killing switch. As a solution,
>he might give me a wireless card so I can just use that.
>
>OSX.2--er, I mean-- Jaguar--supposedly fixed the network setting
>panel so that I could manually set DHCP and subnet mask whatever (I
>can manually set now, but apparently not the one I need to).
>
>If you're intersted, I'll let you know how this all pans out.
>
>Cheers,
>
>
>--Rich
He's a novice. However, this question has passed my knowledge of networking. Can you please read his email and ponder a solution for our good friend, Rich?
-SM
------
>Date: Thu, 19 Sep 2002 21:05:37 -0400
>
>Chris,
>
>Ellen Feiss is the whole reason I got my mac. She's kinda hot in
>that "she's-a-high-college-girl" kind of way. There are whole
>websites dedicated to her. I think you can even get an OSX icon
>with her picture...
>
>Also: Here's my best shot at explaining my network story. If you
>have any ideas, I'm all ears, but it sounds like the CUA-Law network
>is just wired in a way that did NOT anticipate supporting Macs.
>Read it if you're interested from a techincal standpoint, for sheer
>entertainment. Otherwise, have a great day and don't let let the
>thought that I spent 1/2 the night trying to write this all out even
>cross your mind. ;-)
>
>I talked with CUA-Law's network guy. He explained that 1. The law
>school network runs as a sub-branch of the university network (keep
>the distinction in mind as you read on), and 2. on the CUA network,
>the gateway and the stream come in on 2 different DHCP addresses (?)
>or subnet masks or whatever (that allows them to separate students
>from admin., for network security). On Windows 2000, they just
>manually change the setting, but OSX.1 assumes the gateway and
>stream come in on the same... thing.
>
>I hooked up my G4 (looking all cool, flashing my titanium and
>whatnot)and showed him that I was sending (some) ping and receiving
>(lots of) ping. The little ethernet light was going "blink blink
>blink." Obviously, we were getting a feed.
>
>We played with the apple talk "on" button and managed to get the
>connection up... in his office. He thinks were were piggy-backing
>on the university network's appletalk zone. The catch is, the law
>school is wired a little differently.
>
>The problem on the law school network is that every other network
>connection that students can access goes through a switch that
>doesn't have the appletalk zone turned on.
>
>Anyway, I left him scratching his head trying to figure this problem
>out. I don't know how the CUA network compares to most systems, but
>it seems like they should just enable the appletalk zone on the
>switch machine and voila! He said that would take some programming,
>and there's only one guy on campus certified to do that, so it would
>take about... 10 years.
>
>Anyway, all is not lost. They're piloting a wireless network, which
>happens NOT to go through this mac-killing switch. As a solution,
>he might give me a wireless card so I can just use that.
>
>OSX.2--er, I mean-- Jaguar--supposedly fixed the network setting
>panel so that I could manually set DHCP and subnet mask whatever (I
>can manually set now, but apparently not the one I need to).
>
>If you're intersted, I'll let you know how this all pans out.
>
>Cheers,
>
>
>--Rich
From what I can tell, there's not enough description of the problem to diagnose and suggest a solution.
You appear to be talking about two completely different things.
First, there's the subnet used for the TCP/IP configuration as handed out by the DHCP server.
For a start, if that's wrong the problem lies with the DHCP server, not with the Mac. The network administrator needs to make sure the DHCP server is handing out the right subnet.
That said, you can manually change it anyway, regardless of what the DHCP Server provides. Just open a terminal window and run (assuming built-in ethernet):
sudo ifconfig en0 netmask <netmask>
where <netmask> is the netmask you're supposed to use.
Now, the second problem you describe is AppleTalk since they're running switches/routers that are not handling AppleTalk.
No biggie. All recent versions of AppleTalk have supported the ability to run over a TCP/IP connection. For example, if you want to connect to an AppleShare server, you can 'Connect to Server... afp://ip.address.dom/' and it'll run over a TCP/IP connection.
What you do lose with this setup is the ability to browse the network and see available servers, printers, etc. that aren't on the local AppleTalk subnet, but that's about it.
Neither of these issues should be showstoppers.
You appear to be talking about two completely different things.
First, there's the subnet used for the TCP/IP configuration as handed out by the DHCP server.
For a start, if that's wrong the problem lies with the DHCP server, not with the Mac. The network administrator needs to make sure the DHCP server is handing out the right subnet.
That said, you can manually change it anyway, regardless of what the DHCP Server provides. Just open a terminal window and run (assuming built-in ethernet):
sudo ifconfig en0 netmask <netmask>
where <netmask> is the netmask you're supposed to use.
Now, the second problem you describe is AppleTalk since they're running switches/routers that are not handling AppleTalk.
No biggie. All recent versions of AppleTalk have supported the ability to run over a TCP/IP connection. For example, if you want to connect to an AppleShare server, you can 'Connect to Server... afp://ip.address.dom/' and it'll run over a TCP/IP connection.
What you do lose with this setup is the ability to browse the network and see available servers, printers, etc. that aren't on the local AppleTalk subnet, but that's about it.
Neither of these issues should be showstoppers.