Network Weirdness

OK, so there's this one website that we use for work travel planning. I can't get to it from either of our Macs at home. On the Macs, the site just hangs while it pretends to load. However, the site loads fine on a PC from home. I figured there was something wrong with the site.

Turns out that here in the airport, I can get to the website with my Mac.

What's up with that? What could my network be doing that would only affect Macs?

6 thoughtful messages from friendly readers:

Bowie Mike said...

I had a strange network issue that I was able to fix, but I still don't fully understand it. There is a TCP/IP related setting called MTU. They made changes to the network at work five years back, and I and another co-worker suddenly had trouble with connecting to our work machines from home using Remote Desktop. The only thing that would resolve it is changing the MTU setting on my desktop PC at home. However, the setting on the PC could only be changed with a utility program. Not sure how this can be changed on a Mac. My co-worker later upgraded to FIOS, and I thought that his modem also had an MTU setting that he had to adjust.

The default setting was 1300, and I experimented with changing it until I determined that a setting of 1400 solved my problem.

I still do not completely understand what this setting is and how it works. I also had to get over the fact that they changed something at work, and I had to change something at home to compensate. I just figured that if they broke it, they should fix it. Since I got it to work, I dropped my attempts to understand it fully. I later had the same problem from a laptop while using a hotel wireless LAN, and I was able to change the MTU setting on the laptop to get it to work.

I hope this doesn't send you on a wild goose chase. Good luck with this and the avatar.

AbbotOfUnreason said...

Huh. Interesting stuff. I searched around for MTU and it seems to have to do with how big or small the data is chunked up. It looks pretty easy to change on the Mac, but I'll wait until I'm back at home. I found another place that says the router and all the computers in the house have to have the same value. I can't think of anything else to try, that's for sure.


Bowie Mike said...

I have a LinkSys router, and I never changed anything there to resolve the problem that I had. Maybe my PC and router were different all along, and the end result was that I synced them up. The behavior I was experience was really bizarre. Remote desktop would work, but only after the VPN connection had been active for over 10 minutes. Really bizarre.

AbbotOfUnreason said...

Oh, that problem. I had exactly the same problem. It went on for months and then one day just went away without me doing anything. I always figured the guys in the office did something without telling anyone.

AbbotOfUnreason said...

Excellent! The macs automatically sync with the router and I changed the router from 1554 to 1500 and the site loads fine now. I'm very happy. Thanks!

Bowie Mike said...

Wow, for once I have said something useful in a blog comment! There is a first for everything. Glad to hear it worked. And isn't that nice that the Macs just worked once the router was changed - automatically? That's what baffled me about the MTU setting is that I was under the impression that you plug components into a network, and they figure things out automatically. I didn't think you would ever have to "tune" a network. They're just supposed to work, right?!?!