Mac OS X and Internet Sharing

[Ledgem]

Greetings all! Believe it or not, this isn't related to my recent topic about using a Mac system as a proxy server (that's still being worked on, but one of the sewer pipes leaked for the second time in my office, resulting in a mad rush to power everything down and move computers and drives away from the leak area. So, no progress on that for now, and I'm praying that I have no water damage). This time, I'm attempting to share the internet from my Macbook Pro to my girlfriend's laptop.

In past internet sharing experiences, I'd share my ethernet connection with her by setting the system to act as a wireless access point. This worked perfectly fine. The problem is that more recently her computer gets finnicky about wireless connections and as a result she has problems using our apartment's wireless. I figured that this was a simple solution - I'd just share my wireless connection through ethernet with her. It didn't work, because her system wouldn't take a proper IP and she couldn't use the internet.

Now, at work I use a G5 system that has two ethernet ports. I've shared the connection to a Dell XPS system, using a regular ethernet cable, without a problem (other than the fact that IT services caught me and didn't like that setup). I was surprised that an older system would be able to do it with such ease (MDI/MDI-X capable ethernet card), but figured that maybe the problem was my ethernet cable. No big deal - I went on eBay and got a relatively cheap crossover cable. Confident that this would fix the issue, I was distraught to find that it still doesn't work.

I've Googled around and can't find anything on this. Usually people are trying to share their internet with the PC acting as the host, and they run into problems. This makes me think that either nobody is trying to do what I'm doing, or it works so effortlessly that I must be in the extreme minority.

If it helps, here are some of the messages that appear in my console while my system is connected to my girlfriend's. Note that these are the exact same messages that appear when using a regular ethernet cable:

2/1/08 9:10:54 PM kernel AppleYukon2 - en0 link active, 100-Mbit, full duplex, flow control disabled port 0 
2/1/08 9:10:55 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet8(7) Flags 8863 Family  2 192.168.148.1 has different family: 0 
2/1/08 9:10:55 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet1(8) Flags 8863 Family  2 192.168.188.1 has different family: 0 
2/1/08 9:10:55 PM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/1/08 9:10:55 PM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/1/08 9:10:57 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet8(7) Flags 8863 Family  2 192.168.148.1 has different family: 0 
2/1/08 9:10:57 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet1(8) Flags 8863 Family  2 192.168.188.1 has different family: 0 
2/1/08 9:10:57 PM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/1/08 9:10:57 PM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/1/08 9:11:01 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet8(7) Flags 8863 Family  2 192.168.148.1 has different family: 0 
2/1/08 9:11:01 PM mDNSResponder[25] getifaddrs ifa_netmask for vmnet1(8) Flags 8863 Family  2 192.168.188.1 has different family: 0 
2/1/08 9:11:01 PM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/1/08 9:11:01 PM mDNSResponder[25] SetupAddr invalid sa_family 0

And it repeats. I've looked up some of those messages and couldn't find anything. I've disabled AppleTalk on my ethernet adapter and it made no difference. The only things that I haven't tried were assigning a static IP to my or my girlfriend's laptop(s). This isn't a critical issue, but I'd like to get to the bottom of it.

Thanks for any help and advice you can provide.

[Epyon9283]

The only relevant line in that log output there is the first one. The rest of the lines are related to vmware's vmnet interfaces. You should be able to ignore those.

That line only states that it detects a link on the en0 interface.

Look for messages from bootpd in the console. Should look like this:

Feb  2 10:40:27 Mac-Pro bootpd[47320]: DHCP REQUEST [en1]: 1,0:17:f2:e6:8d:6b <MacBook-Pro>

If you don't see anything then its possible that the other machine isn't properly communicating or that its just not sending out a DHCP request. I would try using a static address on the other machine. Set it to an address on the 192.168.2.0/24 network. The gateway and dns server should be set to 192.168.2.1.

[Ledgem]

Originally Posted by Epyon9283

If you don't see anything then its possible that the other machine isn't properly communicating or that its just not sending out a DHCP request. I would try using a static address on the other machine. Set it to an address on the 192.168.2.0/24 network. The gateway and dns server should be set to 192.168.2.1.

I looked for a message from bootpd but there weren't any. Even using a static IP address the PC couldn't access the internet. Windows seems to default the subnet mask to 255.255.255.0, but I set it to 255.255.0.0 - using either of the two didn't make a difference, though.

I'd need to test this with a different computer to see where the problem really lies, but do you think that VMWare's network interfaces are interfering? After just enabling internet sharing, here's what the log shows:

2/2/08 11:44:17 AM com.apple.launchd[1] (com.apple.InternetSharing) Unknown key: SHAuthorizationRight 
2/2/08 11:44:17 AM named[2819] starting BIND 9.4.1-P1 -c /etc/com.apple.named.conf.proxy -f 
2/2/08 11:44:18 AM named[2819] running 
2/2/08 11:44:18 AM mDNSResponder[25] getifaddrs ifa_netmask for vmnet8(7) Flags 8863 Family  2 192.168.148.1 has different family: 0 
2/2/08 11:44:18 AM mDNSResponder[25] getifaddrs ifa_netmask for vmnet1(8) Flags 8863 Family  2 192.168.188.1 has different family: 0 
2/2/08 11:44:18 AM mDNSResponder[25] SetupAddr invalid sa_family 0 
2/2/08 11:44:18 AM mDNSResponder[25] SetupAddr invalid sa_family 0

And when the ethernet link is established, mDNSResponder shows the same messages, as in my first post.

[Epyon9283]

Changing the netmask to something it shouldn't be will only break stuff.

I have vmware installed as well and get the same messages in my logs. Doesn't seem to have an effect on internet sharing on my Machine.

[Ledgem]

I guess I'll have to test this with other systems to determine which system the problem is with. If you (or anyone else) has any other ideas, please let me know.

Thanks Epyon9283!