Mamp PRO and Dynamic DNS: can't access outside LAN

Since my router has a DDNS option, I configured Dyndns service on the config interface... I installed Dyndns Updater, since my ISP doesn't provide static IP, the updater is up and running.

Oops, so you have two Update Clients running? Is your DynDNS hostname already blocked due to abusive updates? If not, wait a while, and it will be! Never ever run more than one Update Client against a hostname!

If you do a "dig +noall +answer http://yourname.dyndns.org", does this show a private, internal IP address or a public, external IP address?

I disabled Web Sharing option on my Sharing preferences

This may be a problem.

if I check with OpenPort tool port 8888 is open.

Is it, still?

I configured MAMP Pro using Dyndns account settings

What items of your account settings would this be?

Now I can access my Dyndns address through my localhost

It could be that you have defined your DynDNS hostname in your hosts file? It rather happens vice versa, that you can't reach your local webserver using an external name or IP address (due to many routers not supporting loopback), but can reach your webserver from outside only with the DynDNS hostname. Can you reach your webserver from another computer within your LAN using its internal IP address?

And as VikingTiger said, knowing your hostname would certainly help us to help you.

There could be many causes. You say that everything worked as expected on Windows XP. Then it sounds like something must have changed since then. Can you think of anything you did differently? Are the old port forwarding rules for the Windows XP computer still enabled on the router? If yes, does that still work as before?

I assume you have some kind of DSL or cable modem between the Sitecom device and the ISP?

If you are willing to post your hostname, it might be simpler for us to help you determine the nature of the problem.

VikingTiger, thanks for replying my question: you're right, I should have specified that I have a DSL connection and I'm connecting to the router from my Mac Book using wi-fi (Airport). I tried to connect to the router with a cable, but got the same results, so I don't think the problem is the airport connection.

Regarding my XP configuration: I just used the same settings I had on WinXp, thinking that if it worked on Win-Xamp then it should work using Mac+Mamp pro. The old port forwarding rules are still enabled on my router, nonetheless I checked them with CheckPort and they result open, my ISP provider is the same, since I'm not using my old Windows laptop, I even assigned its old IP address to the Mac, so I didn't even changed my LAN settings. The only difference is that on Xamp I had to edit the Apache config file to get the port 8888 open, even if it wasn't specified in many tutorials. But in my case port 8888 IS open on the Mac. I tried also port 80: port is open, but the page doesn't show.

Is there anything else I should check?

I just read RotBlitz reply:

Well, honestly I didn't understand that the DDNS option on the router is actually an updater... sorry, but I'm a newbie. However, I disabled Dyndns Updater, but the result doesn't change.

Regarding "Web sharing" option: I disabled it 'cause I read on some Mac tutorials that this could cause conflicts. In facts, if I enable it, I cannot see my website neither on the Mac nor from outside my Lan.

Yes, port 8888 is stil open, as port 80, for what it's worth it.

Regarding Mamp Pro, here's what I did: I went to the "Server" window, then on the 'Dynamic DNS tab' and wrote my dyndns username + password. Then in the "hosts" window I added my hostname hots list, the specified my hostname in the Server name field, specified port 8888 and http://dyndns.com as the service, then checked the disk location of my website folder and checked the permissions, finally defined an alias.

As you suggested I tried to access the website through another computer on the LAN but I can't see the website.

My hostname is http://kikaweb.gotdns.com, I didn't post before 'cause I can't leave the computer on 24h/day.

When I say I can't see my website, I mean that the browser can't establish any connection with the hostname. I can't see any 404 or 403 error, 'cause there's no access to the 'server'.

The only difference is that on Xamp I had to edit the Apache config file to get the port 8888 open, even if it wasn't specified in many tutorials. But in my case port 8888 IS open on the Mac.

Perhaps you already know this, but I will mention it just in case:
For Apache to be able to respond to connections on port 8888 (or any other port), it must be configured to listen on that port. Apache is able to listen on multiple ports at once, as well, but it must always be specified in Apache's configuration which ports it should listen on.

I tried also port 80: port is open, but the page doesn't show.

Hmm. When you say that the page does not show, are we talking about the webserver not responding at all, or are you receiving an error message, such as "404 Not Found" or "403 Forbidden" or similar?

If you have a DSL modem and that modem is not in bridge mode then you'll need to first forward the port(s) from the modem to the router and then from the router to the device, having ensured that the device has a fixed IP address on your LAN (see here).

That said, if you can't access it from another computer on the LAN it says that your problem has to be with the host running MAMP, or the MAMP configuration. Check that the port is open in any software firewall running on the Mac (there is one built in) and that MAMP isn't listening only on loopback.

Oh, and it sounds like you're running THREE update clients - the one in the router, the software client and the one built into MAMP. Before your account is blocked for abuse you must disable all but one, as RotBlitz has already said.