Demon in my network

[HazMatt]

Recently the shared database files running on FileMaker Server 5 on Windows NT have disappeared from the Remote Hosts open screen. Neither the server nor the shared file appears. The auto-opener file I have distributed to all my users simply fails. The files are still being hosted, but the only way to bring them up is to Specify Host... and enter the IP address of the computer hosting FM Server.

I have witnessed this behavior before on my Mac (OS 9), but only sporadically. Yesterday I noticed it on a Windows computer, and today, it appears to have affected the entire network.

I was messing around with my Scheduled Task backup file and the computer's clock (it was 15 minutes ahead). One other problem I noticed is I can't synchronize time with either time.windows.com or time.nist.gov. But other than that, I didn't change any configuration files. I didn't restart or anything else.

I shared a test database on a Mac OS 9 laptop running FileMaker 6, and that does show up over the network in the Remote Hosts screen... What the heck is going on? :confused:

[QuinTech]

Sounds very much like your server is not accepting broadcast/multicast packets. (Incidentally, why would you use BBcode in your post and then turn BBcode off, you knucklehead? : ) Not only is this the exact behavior i would expect from FM, but it seems likely that both of those time servers send broadcast packets as well.

If you haven't changed any firewall settings or any other configurations, are you sure nobody ELSE has?

J

[HazMatt]

Oh crap, you know what? I forgot - I am running FileMaker Server off of Windows XP Pro now. Ooops!

I made the mistake of installing Service Pack 2 a while ago, and immediately lost all communication FileMaker-wise. I promptly turned off Windows Firewall and everything seemed to return to normal.

I am very naive when it comes to the intracacies of networks, so I'm all ears. Broadcast / multicast packets? Tell me more! : More importantly, how do I rectify the situation? I opened up Windows Firewall and it had a few other tabs with more options that I didn't know what to do with.

--

BBCode is off? There's too many check boxes at the bottom when you post a new message! I thought it was always on... :(

[QuinTech]

Crap. I had a feeling you were going to ask that. This is the part of the call where i usually say, "You'll have to get your network admin to allow multicasts." I'll poke around, but hopefully someone will beat me to the punch. (My solution so far has been to avoid SP2 like the plague. : )

As far as the "why": When the FM service starts, it opens the files on the server for hosting. When a client machine's opener file runs, what it is doing is sending a multicast across the network looking for the file you have specified. So if the name of the file you point the opener to is "ModuleA," then when you launch that file, the client machine sends out a packet across the network asking each remote computer if they have an open file named "ModuleA." The first reply it gets, it opens ModuleA as a remote user on the responding machine (this is part of the reason why it is such a bad idea to open remote files through file sharing).

It makes perfect sense to me that a firewall would restrict such packets; it is not difficult to imagine them being used for nefarious purposes. However, it would be nice if you as a user were given a little more warning that this was going to happen. I'm sure it's there in Micro$oft's documentation, but you're probably aware of exactly how helpful their documentation usually is. (A little off-site and off-topic humor: http://www.bizwarcho.com/articles/article.micropsychic.php )

As for BBCode-- you may have an option in your personal settings to never use BBCode. I think there's something like that there.

J

[QuinTech]

how do I rectify the situation?

One thing you might do, though this is probably not the best solution:

Open Properties for you local area connection (or whatever connection FMS uses). Click the Advanced tab and de-select the option for "Protect my computer blah blah blah." This will completely disable the Windows Firewall.

[HazMatt]

Hmm, I think I'm going to uninstall Service Pack 2 and essentially disable the internet on this computer. All it's doing is hosting FileMaker Server to the LAN. Turning off the internet would be more secure than Service Pack 2 could ever be anyway (I think).

So here's another question: what's the best way to "turn off the internet"? I think the answer is simply to configure the TCP/IP settings without a DNS address...

[HazMatt]

I did what I just posted above and everything is back to normal. And it involved my favorite troubleshooting measure: UNINSTALLING WINDOWS SOFTWARE!

Of course, I am on an especially potent Pro-Mac / Anti-Microsoft sentiment today as I just placed an order for a new Power Mac G5. :