routing problem with imacDV & airport

J

James Bond

Registered
Installed Airport card in my imacDV. From it, I can reach all the machines on my LAN except the router to the internet and of course I cannot get out to internet from the imacDV.

Details are below....but I think the problem is that from the imacDV, the gateway route is Link#5, rather than a mac address as it is for the other machines. Does anyone know better or how to fix this?

my LAN is 192.168.2.*
all machines have subnet 255.255.255.0

Gateway/router: 192.168.2.1
connected to internet cable modem on one side and ethernet hub on the other

Two macs are connected to the ethernet hub
Flatscreen = 192.168.2.100
emac = 192.168.2.104

...in addition to the airport base station, also connected to the hub by its WAN port. Settings in Airport Admin Utility are:
"Internet ": IP address-192.168.2.49, router address 192.168.2.1
"Network": Distribute IP addresses - share a range beginning 192.138.2.90, ending 192.168.2.98

The imacDV has the airport card and is configured as:
imacDV = 192.168.2.90 (set by DHCP from the base station) and router 192.168.2.1

Sample output from the imac below:
[iMac-Downstairs:~] roger% ping 192.168.2.49
PING 192.168.2.49 (192.168.2.49): 56 data bytes
64 bytes from 192.168.2.49: icmp_seq=0 ttl=64 time=5.343 ms
64 bytes from 192.168.2.49: icmp_seq=1 ttl=64 time=2.395 ms
64 bytes from 192.168.2.49: icmp_seq=2 ttl=64 time=2.431 ms
64 bytes from 192.168.2.49: icmp_seq=3 ttl=64 time=2.401 ms
64 bytes from 192.168.2.49: icmp_seq=4 ttl=64 time=2.45 ms
64 bytes from 192.168.2.49: icmp_seq=5 ttl=64 time=2.812 ms
64 bytes from 192.168.2.49: icmp_seq=6 ttl=64 time=2.429 ms
^C
--- 192.168.2.49 ping statistics ---
7 packets transmitted, 7 packets received, 0% packet loss
round-trip min/avg/max = 2.395/2.894/5.343 ms
[iMac-Downstairs:~] roger% ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1): 56 data bytes
^C
--- 192.168.2.1 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet loss
[iMac-Downstairs:~] roger% ping 192.168.2.100
PING 192.168.2.100 (192.168.2.100): 56 data bytes
64 bytes from 192.168.2.100: icmp_seq=0 ttl=64 time=5.635 ms
64 bytes from 192.168.2.100: icmp_seq=1 ttl=64 time=2.675 ms
^C
--- 192.168.2.100 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 2.675/4.154/5.635 ms
[iMac-Downstairs:~] roger% ping 192.168.2.104
PING 192.168.2.104 (192.168.2.104): 56 data bytes
64 bytes from 192.168.2.104: icmp_seq=0 ttl=64 time=7.275 ms
64 bytes from 192.168.2.104: icmp_seq=1 ttl=64 time=6.774 ms
64 bytes from 192.168.2.104: icmp_seq=2 ttl=64 time=2.574 ms
^C
--- 192.168.2.104 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 2.574/5.54/7.275 ms
[iMac-Downstairs:~] roger% netstat -r
Routing tables

Internet:
Destination Gateway Flags Refs Use Netif Expire
default 192.168.2.1 UGSc 5 3 en1
127 localhost UCS 0 0 lo0
localhost localhost UH 55 3818 lo0
169.254 link#5 UCS 0 0 en1
192.168.2 link#5 UCS 5 0 en1
192.168.2.1 link#5 UHRLW 5 14 en1 19
192.168.2.49 0:3:93:e1:1c:13 UHLW 0 7 en1 1171
192.168.2.90 localhost UHS 0 2 lo0
192.168.2.100 0:3:93:96:bc:8 UHLW 0 2 en1 1199
192.168.2.104 0:a:95:cc:14:18 UHLW 0 3 en1 1192
192.168.2.255 ff:ff:ff:ff:ff:ff UHLWb 1 1 en1
 
[iMac-Downstairs:~] roger% ifconfig
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
inet6 ::1 prefixlen 128
inet6 fe80::1 prefixlen 64 scopeid 0x1
inet 127.0.0.1 netmask 0xff000000
gif0: flags=8010<POINTOPOINT,MULTICAST> mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:0a:27:df:fe:c6
media: autoselect (none) status: inactive
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>
en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::230:65ff:fe0b:af0e prefixlen 64 scopeid 0x5
inet 192.168.2.90 netmask 0xffffff00 broadcast 192.168.2.255
ether 00:30:65:0b:af:0e
media: autoselect status: active
supported media: autoselect
fw0: flags=8822<BROADCAST,SMART,SIMPLEX,MULTICAST> mtu 2030
lladdr 00:0a:27:ff:fe:df:fe:c6
media: autoselect <full-duplex> status: inactive
supported media: autoselect <full-duplex>
 
From what you describe, it sounds like you have two DHCP servers, which means two local networks. Let your router be the router and DHCP server and firewall and do the PPPoE authentication, turn off DHCP on the airport.
 
Yes - I had similar thoughts overnight....but it is not that simple. I have now managed to get a connection working but there is still something wrong. details below and help still sought since the working config is not a preferred one.

Since I was not using the DHCP from the internet router, I disabled it but that did not make any difference. The airport is now the only DHCP server on the LAN.

Working config:
Enable internet sharing on Flatscreen (192.168.2.100)
On Airport base station set internet router to be 192.168.2.100 (prev 192.168.2.1)
Airport base station network: Distribute IP addresses in range 192.168.2.90 to 98
Airport client: IP address 192.168.2.90, router 192.168.2.100 (currently set manually)

this is the config that I am using to type this message. BUT:

Something is wrong. When I ping the broadcast address from airport client (from the others too), I get duplicate responses![

iMac-Downstairs:~] roger% ping 192.168.2.255
PING 192.168.2.255 (192.168.2.255): 56 data bytes
64 bytes from 192.168.2.90: icmp_seq=0 ttl=64 time=0.624 ms
64 bytes from 192.168.2.49: icmp_seq=0 ttl=64 time=3.274 ms (DUP!)
64 bytes from 192.168.2.100: icmp_seq=0 ttl=64 time=5.277 ms (DUP!)
64 bytes from 192.168.2.104: icmp_seq=0 ttl=64 time=312.59 ms (DUP!)
64 bytes from 192.168.2.90: icmp_seq=1 ttl=64 time=1.565 ms
64 bytes from 192.168.2.49: icmp_seq=1 ttl=64 time=4.499 ms (DUP!)
64 bytes from 192.168.2.100: icmp_seq=1 ttl=64 time=8.465 ms (DUP!)
64 bytes from 192.168.2.90: icmp_seq=2 ttl=64 time=0.549 ms
64 bytes from 192.168.2.49: icmp_seq=2 ttl=64 time=3.835 ms (DUP!)
64 bytes from 192.168.2.90: icmp_seq=3 ttl=64 time=0.555 ms
64 bytes from 192.168.2.49: icmp_seq=3 ttl=64 time=3.508 ms (DUP!)
64 bytes from 192.168.2.100: icmp_seq=3 ttl=64 time=6.777 ms (DUP!)
^C
--- 192.168.2.255 ping statistics ---
4 packets transmitted, 4 packets received, +8 duplicates, 0% packet loss
round-trip min/avg/max = 0.549/29.293/312.59 ms

**BUT** now I *can* ping the real internet router....even though it did not respond to the broadcast ping!
[iMac-Downstairs:~] roger% ping 192.168.2.1
PING 192.168.2.1 (192.168.2.1): 56 data bytes
64 bytes from 192.168.2.1: icmp_seq=0 ttl=64 time=3.972 ms
64 bytes from 192.168.2.1: icmp_seq=1 ttl=64 time=3.73 ms
64 bytes from 192.168.2.1: icmp_seq=2 ttl=64 time=10.199 ms
64 bytes from 192.168.2.1: icmp_seq=3 ttl=64 time=5.003 ms
64 bytes from 192.168.2.1: icmp_seq=4 ttl=64 time=3.049 ms
^C
--- 192.168.2.1 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 3.049/5.19/10.199 ms
[iMac-Downstairs:~] roger% netstat -rn
Routing tables

Internet:
Destination Gateway Flags Refs Use Netif Expire
default 192.168.2.100 UGSc 13 1 en1
127 127.0.0.1 UCS 0 0 lo0
127.0.0.1 127.0.0.1 UH 7 12232 lo0
169.254 link#5 UCS 0 0 en1
192.168.2 link#5 UCS 5 0 en1
192.168.2.1 0:3:93:96:bc:8 UHLW 1 5 en1 452
192.168.2.49 0:3:93:e1:1c:13 UHLW 0 37 en1 718
192.168.2.90 127.0.0.1 UHS 0 4 lo0
192.168.2.100 0:3:93:96:bc:8 UHLW 13 13 en1 1132
192.168.2.104 0:a:95:cc:14:18 UHLW 0 0 en1 1150
192.168.2.255 ff:ff:ff:ff:ff:ff UHLWb 0 4 en1
 
>>>**BUT** now I *can* ping the real internet router....even though it did not respond to the broadcast ping! <<

Looking a bit closer at the last posting, I realise that I can ping to 192.168.2.1 because it resolves to the MAC address of 192.168.2.100 which can reach 192.168.2.1 and has Internet Sharing enabled.

So, the question remains.....why can I not get to 192.168.2.1 directly from the wireless client but I can get to all the other devices in the same subnet?
 
Well, I could be wrong...
You still have two compartmented local nets. Make the router do your routing, and make the airport a wireless bridge that doesn't do any routing duty (like DHCP or DNS forwarding).
 
gsahli said:
Well, I could be wrong...
You still have two compartmented local nets. Make the router do your routing, and make the airport a wireless bridge that doesn't do any routing duty (like DHCP or DNS forwarding).
Click to expand...

DONE that but still have the problem. I have removed the checkbox from Distribute IP addresses on the base station Network settings; I believe that it is now configured as a bridge.

Still 192.168.2.1 does not respond to broadcast and is only reachable via 192.168.2.100 from the wireless client.

MORE INFO: routing info from 192.168.2.100 below - **tks** for your help!!

[flatscreen:~] roger% netstat -rn
Routing tables

Internet:
Destination Gateway Flags Refs Use Netif
Expire
default 192.168.2.1 UGSc 26 24102 en0
127 127.0.0.1 UCS 0 0 lo0
127.0.0.1 127.0.0.1 UH 43 250257 lo0
169.254 link#4 UCS 0 0 en0
192.168.2 link#4 UCS 6 0 en0
192.168.2.1 0:50:fc:be:e2:c UHLW 23 12 en0 951
192.168.2.90 0:30:65:b:af:e UHLW 1 100037 en0 796
192.168.2.100 127.0.0.1 UHS 0 508 lo0
192.168.2.104 0:a:95:cc:14:18 UHLW 1 38843 en0 470
192.168.2.255 link#4 UHLWb 4 2393 en0
 
I'm still mostly confused by what you're doing...
Why is internet sharing enabled on ANY computer -- this again gives you multiple subnets. Your router is supposed to to do all the internat sharing (which = routing). Do you have your router setup to do the PPPoE authentication, and firewall, and routing for you?
Draw your little network out from top to bottom ( like a pine tree - single input at top and multiple branches on bottom). The router is the client of your ISP and the Server for everything below. Everything connected to the hub is setup to be a client of the router.

Hope this helps.
 
You are not half as confused as I am! I think I know quite a bit about what I am trying to do but it just does not work the way it should and I cannot figure out why!

The setup is really simple:

Cable modem connects to router (LAN side address=192.168.2.1, external address provided by ISP) which connects to a hub to which two Macs are connected: Flatscreen (192.168.2.100) and emac (192.168.2.104). Also connected to the hub is the airport base station ("Internet address" 192.168.2.49, router 192.168.2.1).

Base station is configured as a "Bridge" (ie Distribute IP addresses is NOT checked in Network tab in Airport Admin utility).

I have ONE wireless client and iMac (192.168.2.90, manually configured with router set at 192.168.2.1 in its TCP/IP settings in control panel).

Problem is that 192.168.2.1 cannot be reached from the wireless station (but I can reach the other machines, so traffic is going through the airport and out onto the LAN.

In my frustration/desperation (as an experiment with nothing to loose), I turned on internet sharing on Flatscreen and set it as the router on the airport base station and I got internet connectivity. I *know* this is not the way to do it but it was the only way I could get it to work, despite what looked like a correct configuration before that!

Seems like I am exhausting your ideas too?
 
As a troubleshooting step - in Network Prefs Pane for all computers, in the TCP/IP tab, set Configure: Using DHCP. For the wired clients make sure it says above that: Show: Built-In Ethernet.
For the wireless client, make sure it says Show: Airport, then check the TCP/IP tab set for DHCP. (You may want to go to Show: Network Port Configurations and drag Airport to the top of the list - but I think that only matters if you have an ethernet cable plugged in, too.)

Good luck.
 
Are these trick questions(!)? I am not using DHCP anywhere.....but YES, the wired clients are all set manually with Show Built-In-Ethernet and the wireless client is set manually with Show Airport.

The only thing that was not done was having Airport at top of the list in Show Network Port Configurations (done now), but I agree that I do not think that is the problem!

think we will both be pleased when we get to the bottom of this....I have been on it now for TWO days!
 
After all, the problem seems to have been with the ethernet cable that I used to connect the airport to the LAN. It is a RED cable and that might mean that it is a cross-over cable (it is an old cable and that was a colour scheme that I recall from years ago that I think I used to warn me that it was cross-0ver).

Anyway, replaced it with another (gray) cable and it all works fine!

I *know* that airport is supposed to be able to deal automatically with cross-over and straight cables but somehow it did not with this one....perhaps it really is faulty? Anyway, I have had enough of this to not want to investigate further....I am just happy that everything is working fine now!

Tks for your help....you could not have suspected this problem! Even I am not sure that this really was the (only) problem but now that it is all working I have no energy to dig deeper into what went wrong.
 
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