I'm not sure how it's happened but for some reason when using a shared internet connection on my iMac (OS X Lion) all internet traffic is now blocked from being sent to my other devices. However things like streaming radio do work.
How can I figure out what's blocking the port used for internet over WiFi?
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 options=2b<RXCSUM,TXCSUM,VLAN_HWTAGGING,TSO4> ether 00:1e:c2:15:e2:2a media: autoselect status: inactive en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500 ether 00:1e:c2:a3:f7:11 inet6 fe80::21e:c2ff:fea3:f711%en1 prefixlen 64 scopeid 0x5 inet 10.0.2.1 netmask 0xffffff00 broadcast 10.0.2.255 inet 169.254.254.145 netmask 0xffff0000 broadcast 169.254.255.255 media: autoselect status: active fw0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 4078 lladdr 00:1f:5b:ff:fe:0a:2a:5c media: autoselect <full-duplex> status: inactive vnic0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 options=3<RXCSUM,TXCSUM> ether 00:1c:42:00:00:08 inet 10.211.55.2 netmask 0xffffff00 broadcast 10.211.55.255 inet6 fe80::21c:42ff:fe00:8%vnic0 prefixlen 64 scopeid 0x7 inet6 ::1 prefixlen 64 media: autoselect status: active vnic1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 options=3<RXCSUM,TXCSUM> ether 00:1c:42:00:00:09 inet 10.37.129.2 netmask 0xffffff00 broadcast 10.37.129.255 inet6 fe80::21c:42ff:fe00:9%vnic1 prefixlen 64 scopeid 0x8 inet6 ::1 prefixlen 64 media: autoselect status: active ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500 inet 10.136.35.37 --> 10.99.195.231 netmask 0xffffff00 utun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1380 inet6 fe80::21e:c2ff:fe15:e22a%utun0 prefixlen 64 scopeid 0xa inet6 fd00:6587:52d7:10c5:21e:c2ff:fe15:e22a prefixlen 64
Your output from ifconfig for en1 shows 2 inet (IP) addresses which is a little confusing and will require more troubleshooting.
The first IP address shown on en1 is 10.0.2.1 which may or may not be right, you would have to check the wireless interface on the computer sharing the connection. I am a little unclear as to whether the iMac is broadcasting its internet connection to share with others or if it's one of the devices that is receiving a shared connection from another.
Either way, unless the sharing system is acting as a DHCP server to hand out IP addresses, chances are you need to configure each device to have an individual IP address.
But then there is this very unusual issue -
en1 also has an IP of 169.254.254.145 which is a result of not getting an IP address from from a DHCP server and is self-assigning a link-local or APIPA address which can not be used when you are trying to access the Internet because the address cannot be routed.
Definition: A feature of Microsoft Windows [and most modern operating systems], APIPA [link-local] is a DHCP failover mechanism for local networks. With APIPA, DHCP clients can obtain IP addresses when DHCP servers are non-functional.
When a DHCP server fails, APIPA allocates IP addresses in the private range 169.254.0.1 to 169.254.255.254. Clients verify their address is unique on the network using ARP. When the DHCP server is again able to service requests, clients update their addresses automatically.
Here is what I recommend to resolve the issue. Hopefully I understood the issue clearly but this is with the understanding that the iMac is the system that is supposed to broadcast the Internet connection and you are connecting other devices to it via WiFi:
Check the configuration of the wireless network interfaces on all devices. If you are using the 10.0.2.x scheme - set the iMac to 10.0.2.1 and the others to 10.0.2.2 through 10.0.2.254 just ensuring that you don't have two devices with the same IP. You will want to set the netmask to 255.255.255.0 on the wireless interface on the iMac as well as all the devices you want to connect - on everything but the iMac, set the default gateway to 10.0.2.1 . Just to be safe, I would manually set the DNS server IP's to 126.96.36.199 and 188.8.131.52 (openDNS) to make sure all your bases are covered.
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