I wrote:

>> If I connect two Macs with an ethernet cable then look for one on the
>> other, I can't find it. I have File sharing turned on, I choose
>> Go/Connect to Server... then I Browse. Nothing. Using 10.34 on both
>> machines. What am I doing wrong?

Small Tree Communications kindly offered this:

> what netmask are you using? 10.34.1.2 and 10.34.2.2 won't see each other if you
> have a netmask of 255.255.255.0. You'd have to use 255.255.0.0.

and, sure enough, I did have 255.255.255.0. Thanks. I changed them
both. Made no difference yet though.

> Gigabit handles cross over automatically. (assuming your machines are gigabit).
> If not, they won't do it.

I don't think they are gigabit ethernet machines. One is a Titanium 400
MHz, the other a 550 Mhz from the early 2000's.

But, in the past, I have never had a problem with auto-configuration.

(BTW the cable is straight-through.)



Jim Schimpf also kindly wrote:

> Try this, go to GO in Finder and Connect to server. In the server
> address window type: afp://<Machine Name>.local Where Machine Name is
> the Computer Name found under Sharing in System Preferences. This
> should find the other box and let select a user account to share.

Unfortunately, nothing.



David C offered more helpful advice:

> Do you have carrier on the ethernet? Since you don't have a hub,
> there are no lights you can look at, but you can check from
> software. Go to a terminal window on each computer and type
> "ifconfig en0" and look at the output. It should look something like
> this:

<snip>

> If you have carrier, please post the output...


Sure thing, David and thank you and the others very much for taking
this time.

First, the Titanium 400 MHz. Its name is Ti-400 and the username is
grh. Its IP address in TCP/IP is 192.168.1.1

Its Terminal output was

Ti400:~ grh$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULT ICAST> mtu 1500
inet6 fe80::203:93ff:fe15:ddb4 prefixlen 64 scopeid 0x4
inet 192.168.1.1 netmask 0xffff0000 broadcast 192.168.255.255
ether 00:03:93:15:dd:b4
media: autoselect (100baseTX <full-duplex>) status: active
supported media: none autoselect 10baseT/UTP <half-duplex>
10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback>
100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX
<full-duplex,hw-loopback>
Ti400:~ grh$

The other machine, the Titanium 550 MHz, has the name Ti-550 and the
same username. Its IP address in TCP/IP is 192.168.1.2.

Its Terminal output was

Ti550:~ grh$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULT ICAST> mtu 1500
inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
inet6 fe80::203:93ff:fe46:7a6c prefixlen 64 scopeid 0x4
inet 192.168.1.2 netmask 0xffff0000 broadcast 192.168.255.255
ether 00:03:93:46:7a:6c
media: autoselect (100baseTX <full-duplex>) status: active
supported media: none autoselect 10baseT/UTP <half-duplex>
10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback>
100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX
<full-duplex,hw-loopback> 1000baseTX <full-duplex> 1000baseTX
<full-duplex,hw-loopback> 1000baseTX <full-duplex,flow-control>
1000baseTX <full-duplex,flow-control,hw-loopback>
Ti550:~ grh$


So I think we can say that the cable is ok, the machines can see each
other and it's only some silly configuration oversight that I'm guilty
of.

The second part of my question concerns connecting to a PC. My friend
tells me that he is running a Virtual Private Network to connect to the
net with a broadband service and, if I could only change one small
thing, I should have access too (provided I can solve the overall
connectivity problem).

The "small thing" he wants me to change is this: Open the Network
preferences, go to Built-in Ethernet/Ethernet.

There, I can see "Ethernet ID 00:03:93:46:7a:6c."

How to modify this?

Cheers guys and thanks again.

GoodGuy <goodguy@adfg.com> writes:
>
> First, the Titanium 400 MHz. Its name is Ti-400 and the username is
> grh. Its IP address in TCP/IP is 192.168.1.1
>
> Its Terminal output was
>
> Ti400:~ grh$ ifconfig en0
> en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULT ICAST> mtu 1500
> inet6 fe80::203:93ff:fe15:ddb4 prefixlen 64 scopeid 0x4
> inet 192.168.1.1 netmask 0xffff0000 broadcast 192.168.255.255
> ether 00:03:93:15:dd:b4
> media: autoselect (100baseTX <full-duplex>) status: active
> supported media: none autoselect 10baseT/UTP <half-duplex>
> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback>
> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX
> <full-duplex,hw-loopback>
> Ti400:~ grh$
>
> The other machine, the Titanium 550 MHz, has the name Ti-550 and the
> same username. Its IP address in TCP/IP is 192.168.1.2.
>
> Its Terminal output was
>
> Ti550:~ grh$ ifconfig en0
> en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULT ICAST> mtu 1500
> inet 192.168.2.1 netmask 0xffffff00 broadcast 192.168.2.255
> inet6 fe80::203:93ff:fe46:7a6c prefixlen 64 scopeid 0x4
> inet 192.168.1.2 netmask 0xffff0000 broadcast 192.168.255.255
> ether 00:03:93:46:7a:6c
> media: autoselect (100baseTX <full-duplex>) status: active
> supported media: none autoselect 10baseT/UTP <half-duplex>
> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback>
> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX
> <full-duplex,hw-loopback> 1000baseTX <full-duplex> 1000baseTX
> <full-duplex,hw-loopback> 1000baseTX <full-duplex,flow-control>
> 1000baseTX <full-duplex,flow-control,hw-loopback>
> Ti550:~ grh$

Yes. Since both sides show the status as active, and they've
auto-selected the same protocol (100baseTX full-duplex), we know
there aren't any physical connectivity issues.

At this point, it falls to IP configuration.

According to the ifconfig output, they have unique addresses in the
same subnet (192.168/16) so you should have IP connectivity between
them.

Check to make sure you don't have any firewall controls active (On the
"Sharing" control panel) on either machine. With the firewall turned
on, only the selected services will work.

Can the two computers ping each other? Drop to a command line and try
the following:

on Ti-400:
$ ping 192.168.1.2

You should see output something like:
PING 192.168.1.2 (192.168.1.2): 56 data bytes
64 bytes from 192.168.1.2: icmp_seq=0 ttl=150 time=0.725 ms
64 bytes from 192.168.1.2: icmp_seq=1 ttl=150 time=0.643 ms
64 bytes from 192.168.1.2: icmp_seq=2 ttl=150 time=0.636 ms
...

(press Ctrl-C to stop the ping program).

If you don't then there's an IP problem. If pings do go through,
then you've got a higher-level problem.

Also try pinging in the reverse direction. You should get the same
result, but it might be informative if you don't.

If you're using Apple's file sharing, make sure both computers are
using AppleTalk (on the Network control panel). If one is and the
other isn't, they may fail to see each other.

> So I think we can say that the cable is ok, the machines can see
> each other and it's only some silly configuration oversight that I'm
> guilty of.
>
> The second part of my question concerns connecting to a PC. My
> friend tells me that he is running a Virtual Private Network to
> connect to the net with a broadband service and, if I could only
> change one small thing, I should have access too (provided I can
> solve the overall connectivity problem).

There are different VPN protocols around. The one that MacOS has
built-in is called PPTP, and is accessible via the Internet Connect
control panel.

Something's fishy if he says he needs VPN software to connect to the
internet. I've never seen an ISP that requires this. He is probably
thinking of something else if he doesn't have a very unusual ISP.

VPN software is typically used over an existing internet connection
to allow secure access to a corporate network. I've never heard of
it being used by an ISP to provide basic access.

> The "small thing" he wants me to change is this: Open the Network
> preferences, go to Built-in Ethernet/Ethernet.
>
> There, I can see "Ethernet ID 00:03:93:46:7a:6c."
>
> How to modify this?

OK. Several ISPs do register your Ethernet MAC address for some
strange reason. They will refuse to allow other MAC addresses to
connect from your site. Because of this, most gateway routers sold
today provide an easy way to configure their internet-facing MAC
address.

As for configuring your Mac's MAC address, it can't be done through
the stock Apple network control panel. The only Ethernet
configuration they offer is speed, duplex and MTU size.

The "ifconfig" command can be used to change an Ethernet MAC
address. But this isn't something I recommend. (And the change
won't stick - you'll have to issue the command after every reboot.)

But I wouldn't recommend this. If you and your friend's computer
share the same MAC address on the same Ethernet network segment, then
you will clobber each other, resulting in messed up connectivity for
both of you.

-- David

This is off topic, but I'm curious,
How can I
A. find out my own IP address?
B. reverse ping myself to test my NetBarrier?

any help, thanx,
GW


David C. wrote:

> Also try pinging in the reverse direction. You should get the same
> result, but it might be informative if you don't.
>

Geoff Welsh <geoffdubya@some.rr.com> writes:
>
> This is off topic, but I'm curious,
> How can I
> A. find out my own IP address?

The easiest way is to open up the "Network" pane of system
preferences and read what you find there.

> B. reverse ping myself to test my NetBarrier?

Log in to some computer beyond your network, if you have an account
on one, and ping yourself.

If you're looking for an open server that does this, I don't know of
any.

-- David

OK.
Here's where this get's interesting, it says my IP address is
192.168.102.100
According to a friend of mine, that's a router IP, so my ISP (I have no
network, just me, at home, paying a bill) essentially blocks me.
This sound right to anyone?
I'm a little over my head but want to learn.
GW


David C. wrote:

> Geoff Welsh <geoffdubya@some.rr.com> writes:
>
>>This is off topic, but I'm curious,
>>How can I
>>A. find out my own IP address?
>
> The easiest way is to open up the "Network" pane of system
> preferences and read what you find there.
>
> -- David

In article <P9zZc.16448$aB1.319@twister.socal.rr.com>,
Geoff Welsh <geoffdubya@some.rr.com> wrote:

> OK.
> Here's where this get's interesting, it says my IP address is
> 192.168.102.100
> According to a friend of mine, that's a router IP, so my ISP (I have no
> network, just me, at home, paying a bill) essentially blocks me.
> This sound right to anyone?
> I'm a little over my head but want to learn.
> GW
>
>
> David C. wrote:
>
> > Geoff Welsh <geoffdubya@some.rr.com> writes:
> >
> >>This is off topic, but I'm curious,
> >>How can I
> >>A. find out my own IP address?
> >
> > The easiest way is to open up the "Network" pane of system
> > preferences and read what you find there.
> >
> > -- David

Your friend is right-- that's the sort of IP address given out by a
router to computers on a local area network.

How do you connect to the Internet? It would appear that some gadget --
most commonly a router connected to a cable or DSL modem, but possibly
the modem itself-- is generating that address.

This, by the way, is a good thing... it means that hackers probing for
vulnerable computers don't get a chance to see your computer-- they only
see the router, which are generally less vulnerable.

=======================================
remove 'nospam' from email address before sending, please!

Alan's website: www.zisman.ca

Alan Zisman wrote:

> In article <P9zZc.16448$aB1.319@twister.socal.rr.com>,
> Geoff Welsh <geoffdubya@some.rr.com> wrote:
>>OK.
>>Here's where this get's interesting, it says my IP address is
>>192.168.102.100
>>According to a friend of mine, that's a router IP, so my ISP (I have no
>>network, just me, at home, paying a bill) essentially blocks me.
>>This sound right to anyone?
>>I'm a little over my head but want to learn.
>>GW

> Your friend is right-- that's the sort of IP address given out by a
> router to computers on a local area network.
>
> How do you connect to the Internet? It would appear that some gadget --
> most commonly a router connected to a cable or DSL modem, but possibly
> the modem itself-- is generating that address.
Cable modem.
Yeah, I heard it's good for security, but if I ever wanted to connect to
my computer remotely, which I hear OSX is great for, I wouldn't be able
to find it, right?
GW

Geoff Welsh <geoffdubya@some.rr.com> writes:
>
> OK.
> Here's where this get's interesting, it says my IP address is
> 192.168.102.100
> According to a friend of mine, that's a router IP, so my ISP (I have
> no network, just me, at home, paying a bill) essentially blocks me.
> This sound right to anyone?
> I'm a little over my head but want to learn.

Based on what you already posted, it would appear that the router you
have installed between the Mac and the cable modem has assigned this
address to the Mac.

This address is in what's known as private address space. In other
words, it's only significant within your LAN (that is, on your side
of the router.) The rest of the internet will not be able to reach
your at that address.

If your router works like most inexpensive gateway routers, it is
running a protocol called NAT (Network Address Translation).

The router is getting a public IP address from your broadband
provider. It gives out private-space addresses to all the computers
on your LAN. It translates the addresses for all packets that go
between your LAN and the internet, keeping track of which of your
computers have initiated which connections - so that everybody on
your LAN can share the single IP address your broadband provider has
given you.

If you look at the router's configuration (you can usually do this by
pointing a web browser at 192.168.1.1 - which is a private address
that most routers use for local configuration) you should be able to
see what address your broadband provider gave the router.

This is the address that the rest of the world sees you as. Or more
exactly, it is the address that the rest of the world sees your
entire LAN as.

Unfortunately, this means connecting from the outside isn't that
simple. If you simply try to access your computer at that address,
the packets will get to your router, but they won't go any further.
This is because the router won't know what address on your LAN they
should be sent to. (Even if you only have one computer on the LAN,
the router doesn't know that.)

You can configure something called port forwarding to redirect
specific services to specific computers on your LAN, but it's not
something I recommend for the inexperienced. If you don't set it up
right, you can open up some very big security holes - undermining
everything gained by using the router.

-- David

David C. wrote:
> Geoff Welsh <geoffdubya@some.rr.com> writes:
>
>>OK.
>>Here's where this get's interesting, it says my IP address is
>>192.168.102.100
>>According to a friend of mine, that's a router IP, so my ISP (I have
>>no network, just me, at home, paying a bill) essentially blocks me.
>>This sound right to anyone?
>>I'm a little over my head but want to learn.
>
>
> Based on what you already posted, it would appear that the router you
> have installed between the Mac and the cable modem has assigned this
> address to the Mac.
>
> This address is in what's known as private address space. In other
> words, it's only significant within your LAN (that is, on your side
> of the router.) The rest of the internet will not be able to reach
> your at that address.
>
> If your router works like most inexpensive gateway routers, it is
> running a protocol called NAT (Network Address Translation).
>
> The router is getting a public IP address from your broadband
> provider. It gives out private-space addresses to all the computers
> on your LAN. It translates the addresses for all packets that go
> between your LAN and the internet, keeping track of which of your
> computers have initiated which connections - so that everybody on
> your LAN can share the single IP address your broadband provider has
> given you.
>
> If you look at the router's configuration (you can usually do this by
> pointing a web browser at 192.168.1.1 - which is a private address
> that most routers use for local configuration) you should be able to
> see what address your broadband provider gave the router.
>
> This is the address that the rest of the world sees you as. Or more
> exactly, it is the address that the rest of the world sees your
> entire LAN as.
>
> Unfortunately, this means connecting from the outside isn't that
> simple. If you simply try to access your computer at that address,
> the packets will get to your router, but they won't go any further.
> This is because the router won't know what address on your LAN they
> should be sent to. (Even if you only have one computer on the LAN,
> the router doesn't know that.)
>
> You can configure something called port forwarding to redirect
> specific services to specific computers on your LAN, but it's not
> something I recommend for the inexperienced. If you don't set it up
> right, you can open up some very big security holes - undermining
> everything gained by using the router.
>
> -- David
There must have been some miscommunication...
I do NOT have a router. I do NOT have a LAN.
I have an iMac, and a cable modem. That's why I was fascinated to find
out that my IP address seems to be a router #, and wondered if this
means I cannot remotely connect to my home.
GW.

Geoff Welsh <geoffdubya@some.rr.com> writes:
>
> There must have been some miscommunication...
> I do NOT have a router. I do NOT have a LAN.
> I have an iMac, and a cable modem. That's why I was fascinated to
> find out that my IP address seems to be a router #, and wondered if
> this means I cannot remotely connect to my home.

It is possible that your ISP is giving you an address in private
space, with the ISP performing network address translation for you.

If this is the case then there is no way you can receive connections
from the internet - you have no way of knowing what your externally-
visible address is, and no way of configuring the ISP's router to
send unsolicited traffic to you.

If they're doing this, it may also break standard protocols (like FTP
and various streaming media) that send you data on channels that you
did not initiate. NAT packages today are usually smart enough to
snoop all your packets to auto-configure this sort of thing, but they
need constant updating as new protocols come out.

(They could also have a block of public addresses, with a 1:1 match
between the private addresses and the public ones. Which would serve
absolutely no purpose, but but has been done by some brain-dead ISPs.)

If this is really what's happening, I woldn't worry about it, but it
will mean that there is no way for you to even consider remote- login.
Maybe that's what your cable company wants - to charge you extra
money for a "server-compatible" business account before you can
remote login.

If you have an alternative for broadband, you may want to consider
switching companies. What you're describing sounds like they are
either heavy-handed greedy pigs or clueless idiots. I have a
personal aversion to doing business with people like this.

-- David

shamino@techie.com (David C.) wrote:

> Geoff Welsh <geoffdubya@some.rr.com> writes:
> >
> > There must have been some miscommunication...
> > I do NOT have a router. I do NOT have a LAN.
> > I have an iMac, and a cable modem. That's why I was fascinated to
> > find out that my IP address seems to be a router #, and wondered if
> > this means I cannot remotely connect to my home.
>
> It is possible that your ISP is giving you an address in private
> space, with the ISP performing network address translation for you.

It's more likely that the cable modem itself is doing NAT. What brand is
it? Does it have a 'configuration page' that you can access from a
browser?

There are a number of web sites which will tell you your publicly-visible
IP address. http://whatismyip.com/ is probably the easiest to remember.
:)

aranders@insightbb.com (Alan Anderson) writes:
>
> It's more likely that the cable modem itself is doing NAT. What
> brand is it? Does it have a 'configuration page' that you can
> access from a browser?

Why would an ISP do this? It doesn't gain them anything and it makes
life much more difficult for customers - and it means they can't use
el-cheapo modems.

Furthermore, it's been my experience that broadband providers lock
down the modems they distribute, so you won't be able to change any
configuration without knowing the password assigned by the ISP -
which they won't give out to customers.

Do you actually know of cable companies that do this "for" their
customers?

> There are a number of web sites which will tell you your
> publicly-visible IP address. http://whatismyip.com/ is probably the
> easiest to remember.

But this will be useless for allowing remote access if that address is
shared with other customers, or if the modem's configuration is locked
out.

-- David

shamino@techie.com (David C.) wrote:

> aranders@insightbb.com (Alan Anderson) writes:
> >
> > It's more likely that the cable modem itself is doing NAT. What
> > brand is it?...
>
> Do you actually know of cable companies that do this "for" their
> customers?

It's not the cable company doing it. It's the cable *modem*. Some of
them have a basic router built in (often advertised as a "firewall",
though it's not really the same thing). That's why I asked what brand it
is.

> > There are a number of web sites which will tell you your
> > publicly-visible IP address. http://whatismyip.com/ is probably the
> > easiest to remember.
>
> But this will be useless for allowing remote access if that address is
> shared with other customers, or if the modem's configuration is locked
> out.

The way a DOCSIS cable modem works, you won't end sharing your public IP
unless the ISP actually does NAT between the internet and its
subscribers. I've never heard of one that does that.

The modem configuration almost never needs to be touched, and usually
can't be without special software. It's the associated router packaged
with it that would have the http-accessable page.

Alan Anderson wrote:

> shamino@techie.com (David C.) wrote:
>
>
>>Geoff Welsh <geoffdubya@some.rr.com> writes:
>>
>>>There must have been some miscommunication...
>>>I do NOT have a router. I do NOT have a LAN.
>>>I have an iMac, and a cable modem. That's why I was fascinated to
>>>find out that my IP address seems to be a router #, and wondered if
>>>this means I cannot remotely connect to my home.
>>
>>It is possible that your ISP is giving you an address in private
>>space, with the ISP performing network address translation for you.
>
>
> It's more likely that the cable modem itself is doing NAT. What brand is
> it?

It says Toshiba PCX 2500 Cable Modem

Does it have a 'configuration page' that you can access from a
> browser?
>
IDK
> There are a number of web sites which will tell you your publicly-visible
> IP address. http://whatismyip.com/ is probably the easiest to remember.
> :)
Thanks
GW

Alan Anderson wrote:


> There are a number of web sites which will tell you your publicly-visible
> IP address. http://whatismyip.com/ is probably the easiest to remember.
> :)
That says 66.91.176.100 which is obviously quite different from what my
network info in System Prefs says (192.168.102.100)

GW