Internet Sharing from WiFi to Ethernet doesn't work in Mountain Lion 10.8.4

Question

Level 1

8 points

Internet Sharing from WiFi to Ethernet doesn't work in Mountain Lion 10.8.4

I'm trying to share my WiFi connection on a Macbook Air to a USB-to-Ethernet adapter. I'm very, very, very frustrated at how Apple seems to have broken this feature that used to work on earlier software releases. I've tried dozens of different fixes and can't even keep them straight anymore.

When I turn on Internet connection sharing, 'ifconfig' gives me:

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384

options=3<RXCSUM,TXCSUM>

inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1

inet 127.0.0.1 netmask 0xff000000

inet6 ::1 prefixlen 128

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

ether 04:0c:ce:db:3f:78

inet6 fe80::60c:ceff:fedb:3f78%en0 prefixlen 64 scopeid 0x4

inet 192.168.2.37 netmask 0xffffff00 broadcast 192.168.2.255

media: autoselect

status: active

p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304

ether 06:0c:ce:db:3f:78

media: autoselect

status: inactive

utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380

inet6 fe80::3590:a853:773c:8914%utun0 prefixlen 64 scopeid 0x6

inet6 fd0f:571b:bba6:6428:3590:a853:773c:8914 prefixlen 64

en1: flags=863<UP,BROADCAST,SMART,RUNNING,SIMPLEX> mtu 1500

ether c8:a0:30:af:84:4c

media: autoselect

status: active

bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

ether ac:de:48:05:fe:97

Configuration:

priority 0 hellotime 0 fwddelay 0 maxage 0

ipfilter disabled flags 0x2

Looking at other answers, I've tried adding my 'en1' USB Ethernet adapter with 'sudo ifconfig bridge0 addm en1', but it gets rejected:

ifconfig: BRDGADD en1: Operation not supported on socket

I can add my wifi adapter with 'sudo ifconfig bridge0 addm en0' and I can see it now on the 'bridge0' adapter:

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384

options=3<RXCSUM,TXCSUM>

inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1

inet 127.0.0.1 netmask 0xff000000

inet6 ::1 prefixlen 128

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500

ether 04:0c:ce:db:3f:78

inet6 fe80::60c:ceff:fedb:3f78%en0 prefixlen 64 scopeid 0x4

inet 192.168.2.37 netmask 0xffffff00 broadcast 192.168.2.255

media: autoselect

status: active

p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304

ether 06:0c:ce:db:3f:78

media: autoselect

status: inactive

utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380

inet6 fe80::3590:a853:773c:8914%utun0 prefixlen 64 scopeid 0x6

inet6 fd0f:571b:bba6:6428:3590:a853:773c:8914 prefixlen 64

en1: flags=863<UP,BROADCAST,SMART,RUNNING,SIMPLEX> mtu 1500

ether c8:a0:30:af:84:4c

media: autoselect

status: active

bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

ether ac:de:48:44:19:92

Configuration:

priority 0 hellotime 0 fwddelay 0 maxage 0

ipfilter disabled flags 0x2

member: en0 flags=3<LEARNING,DISCOVER>

port 4 priority 0 path cost 0

Doesn't do me a darn bit of good though. The USB Ethernet connection doesn't respond to any DHCP requests. If I force an IP address on en1 with 'ifconfig en1 192.168.7.1', I lose connectivity.

h56-126:~ jason$ ping 192.168.2.37

PING 192.168.2.37 (192.168.2.37): 56 data bytes

64 bytes from 192.168.2.37: icmp_seq=0 ttl=64 time=0.062 ms

64 bytes from 192.168.2.37: icmp_seq=1 ttl=64 time=0.167 ms

^C

--- 192.168.2.37 ping statistics ---

2 packets transmitted, 2 packets received, 0.0% packet loss

round-trip min/avg/max/stddev = 0.062/0.115/0.167/0.053 ms

h56-126:~ jason$ ping 192.168.2.1

PING 192.168.2.1 (192.168.2.1): 56 data bytes

ping: sendto: No route to host

Request timeout for icmp_seq 0

^C

--- 192.168.2.1 ping statistics ---

2 packets transmitted, 0 packets received, 100.0% packet loss

h56-126:~ jason$ ping 192.168.2.1

PING 192.168.2.1 (192.168.2.1): 56 data bytes

ping: sendto: No route to host

Request timeout for icmp_seq 0

ping: sendto: No route to host

Request timeout for icmp_seq 1

ping: sendto: No route to host

Request timeout for icmp_seq 2

^C

--- 192.168.2.1 ping statistics ---

4 packets transmitted, 0 packets received, 100.0% packet loss

h56-126:~ jason$ route -n get default

route to: default

destination: default

mask: default

gateway: 192.168.2.1

interface: en0

flags: <UP,GATEWAY,DONE,STATIC,PRCLONING>

recvpipe sendpipe ssthresh rtt,msec rttvar hopcount mtu expire

0 0 0 0 0 0 1500 0

h56-126:~ jason$ ifconfig

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384

options=3<RXCSUM,TXCSUM>

inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1

inet 127.0.0.1 netmask 0xff000000

inet6 ::1 prefixlen 128

gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280

stf0: flags=0<> mtu 1280

en0: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500

ether 04:0c:ce:db:3f:78

inet6 fe80::60c:ceff:fedb:3f78%en0 prefixlen 64 scopeid 0x4

inet 192.168.2.37 netmask 0xffffff00 broadcast 192.168.2.255

media: autoselect

status: active

p2p0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 2304

ether 06:0c:ce:db:3f:78

media: autoselect

status: inactive

utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380

inet6 fe80::3590:a853:773c:8914%utun0 prefixlen 64 scopeid 0x6

inet6 fd0f:571b:bba6:6428:3590:a853:773c:8914 prefixlen 64

en1: flags=863<UP,BROADCAST,SMART,RUNNING,SIMPLEX> mtu 1500

ether c8:a0:30:af:84:4c

inet 192.168.7.1 netmask 0xffffff00 broadcast 192.168.7.255

media: autoselect

status: active

bridge0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500

ether ac:de:48:05:fe:97

Configuration:

priority 0 hellotime 0 fwddelay 0 maxage 0

ipfilter disabled flags 0x2

member: en0 flags=3<LEARNING,DISCOVER>

port 4 priority 0 path cost 0

h56-126:~ jason$

I'm at my wit's end.

MacBook Air, OS X Mountain Lion (10.8.4)

Posted on Jul 6, 2013 12:14 PM

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Answer 1

LowLuster

Level 6

12,105 points

Jul 6, 2013 12:38 PM in response to jkridner

How are you connecting to WiFi? Whatever WiFi signal you are using just connect your other devices to that same signal.

Or are you connecting over Cell system 3/4G system. That really isn't WiFi.

Reply

Answer 2

jkridner Author

Level 1

8 points

Jul 6, 2013 12:57 PM in response to LowLuster

LowLuster wrote:

How are you connecting to WiFi? Whatever WiFi signal you are using just connect your other devices to that same signal.

Or are you connecting over Cell system 3/4G system. That really isn't WiFi.

This isn't helpful. I have a device that acts as a USB-to-Ethernet adapter. I'd like to bridge my WiFi connection to that Ethernet connection. Every other major operating system, including Linux, Windows and FreeBSD support this configuration. This is a bug in OS X and it is reasonable to expect it to be fixed rather than made worse version after version.

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Answer 3

jkridner Author

Level 1

8 points

Jul 6, 2013 1:35 PM in response to jkridner

Gave up on the GUI. This script derived from http://blog.netnerds.net/2012/07/os-x-how-to-setup-nat-on-lion-and-mountain-lion / seems to work for me:

gwdev=en0 # This is my WiFi connection (has Internet connection)

targetdev=en1 # This is the USB to Ethernet adapter (to give Internet connection)

/sbin/ifconfig $targetdev down

/sbin/ifconfig bridge0 create

/sbin/ifconfig bridge0 up

/sbin/ifconfig bridge0 addm $gwdev

/sbin/ifconfig bridge0 $HOST_ADDR

/sbin/route add default -interface bridge0 -ifscope bridge0 -cloning

/usr/sbin/sysctl -w net.inet.ip.forwarding=1

/sbin/ipfw add 100 divert natd ip from any to any via $gwdev

/usr/sbin/natd -interface $gwdev -use_sockets -same_ports -unregistered_only -dynamic -clamp_mss -enable_natportmap -natportmap_interface $targetdev

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