bonjour: cannot see remote devices

elliann · #1 March 24th, 2007, 05:49 PM

I am having trouble getting Bonjour working between an iMac and other Macs on the same local Wifi network. It used to work, but recently stopped.

The hardware in play is:
iMac G5 with 10.4.9 -- this is the problem machine.
Airport Express
MacBook Pro and iBook G4

On the iMac, I cannot see any Bonjour services that are not on the iMac. I installed Bonjour Browser, and I can see 5 services from the iMac. All 5 are local: Apple File Sharing, Internet printing protocol, SFTP, SSH, Workgroup manager.

Note that I should at least be able to see the airport base station; the iMac is connected to it and has a DHCP address from it. (Needless to say, airport admin cannot browse to the base station, but it can connect by entering the IP address by hand).

The 2 laptops cannot see anything on the iMac. Everything is connected to the Airport Express with DHCP now, and the subnets are all the same. They are connected to the same base station, I am sure.

The interesting thing is that I can ssh between the macbook and the imac, both when the macbook is outside the LAN, as well as with the 192.168 address of the iMac. So I know that packets are reaching the machines through the base station.

I have turned the firewall off (network preferences) and it is no help. I have rebooted as well. The iBook also cannot see the iMac through iTunes, but the iBook, macbook, and airport express can all see each other.

The only thing I can think of is that somehow the iMac's host name got a "-2" appended to it, and I removed it. So the host name has changed potentially. However, I can't see any trace of either the old nor the new hostname in Bonjour browser anywhere, so I don't know if this matters or not.

I don't know where to start looking any further. Is there some kind of directory/domain thing with bonjour? I don't know how it's supposed to work and I don't know where to begin looking further.

Thanks for your help
Elli

**Captain Code** · #2 March 25th, 2007, 11:13 AM

Check that your subnet masks are the same on both computers. Bonjour is a broadcast technology and will broadcast only on the same subnet. Usually you will set it to 255.255.255.0 on a LAN.

elliann · #3 March 25th, 2007, 12:02 PM

Yes, they're on the same subnet. I've tried it with the iMac getting a DHCP address and a manual one on the 192.168 subnet. No luck either way. My thought was by putting them on the same DHCP server then that would eliminate the router as the cause.

I guess it sounds like a packet issue? I'm close to the point of getting a packet sniffer to see if any bonjour traffic is getting through.

Elli

**Captain Code** · #4 March 25th, 2007, 12:06 PM

It sounds like a firewall issue to me even though I know you said you have it turned off. If the packets were making it to your machine you should be able to see the Bonjour services. Did you do anything to manually change ipfw rules?

elliann · #5 March 25th, 2007, 05:42 PM

I got it working! I have no idea what it was.

I double checked the firewall settings using ipfw list, and it only had 1 line -- allow all. But the "stealth mode" was checked so I turned that off; I don't know if that was somehow on.

Using tcpdump I could see that some of the bonjour packets were getting through. It was like if I hit refresh on the bonjour browser, I could see a packet hit tcpdump -- both on the problem iMac and the macbook.

So I fiddled with the hostname again and rebooted a few times. I'm not sure exactly what did it, but I suspect that there's some kind of service name collision that it resolved in some weird way once. I am not really sure.

Thanks for your help,
Elli