[chasg]

Hi All,

Ok, strange behaviour: I'm trying to ftp from one of my Macs, but can't connect to this particuar ftp address (I _can_ connect to some others I've tried). I get this behaviour in the Terminal as well.

My other Mac _can_ connect to the server in question.

Both Macs are running 10.3.2. The main difference is that the first Mac (the one that can't connect) has just undergone a full reinstall (and so is pretty close to vanilla).

Any ideas anyone?

Chas

[chasg]

an update: I just discovered that while I can _open_ other ftp sites, files that I upload don't contain any data (are being reported as zero K).

What the??

[car1son]

More info would be helpful... Are you using dial-up to connect these Macs to the same ISP? Or are both these Macs sharing a broadband router? Is the problem only uploading, or do downloads also come out zero bytes?

I assume you've considered any changes you made (and perhaps since forgotten) to the working Mac with the older install, such as changing the MTU size?

[chasg]

Hi car1son, thanks for replying.

Both Macs are sharing an ADSL connection via a router.

The problem Mac seems to be downloading ok, but a subsequent upload of the same file I had just downloaded, failed.

No changes to anything like MTU size (that I remember!). I tend to leave things in a pretty vanilla state.

I'd be grateful for any ideas you may have,

Chas

[car1son]

Upload problems are a symptom of an MTU size problem (among other possibilities).

On Panther I believe you can adjust this in the Network Prefernces, Show Built-in Ethernet, Ethernet tab, Configure: Manually (Advanced.) the default it probably 1500, while 1492 is often right for ADSL. Compare the values on the two systems.

If I'm wrong about how to see it in Panther, you can check it from the Terminal with the ifconfig -a command.

Code:
[HMSIndefatigable:~] car1son% /sbin/ifconfig -a
 [...]
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1492
        inet6 fe80::203:93ff:fe07:11aa%en0 prefixlen 64 scopeid 0x4 
        ether 00:03:93:07:11:aa 
        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>

(Note mine is set to 1492 on first line of en0: description.)

[chasg]

Hi again car1son,

Well, no luck.

You were right, I can adjust the MTU size in the Network preferences. I messed around with the various settings there, setting MTU to 1492, and then other values down to the minimum 72.

I also experimented with the ethernet speed and duplex method (worth a shot). No joy.

Well, I'm now pretty sure that it's not MTU size (but thanks very much for the pointer). If you've got any other ideas, I'd love to hear them. If not, thanks for the time you _have_ taken!

On the machine that _does_ work, the settings are on automatic.

One thing occurs to me: if one machine works, and the other does not (all settings, hopefully, being equal), would some sort of fault with the ethernet hardware be a possibility? (but would could be a hardware fault that still allowed for basically all other TCP/IP communications?)

<sigh>

Chas