So here is the situation :
I have an ADSL modem/router (the dsl-504t from DLink). Two computer are connected to it throught ethernet. The first (I'll call it A) runs under Mandriva LE 2005 RC2, the second one (B) is with Mandriva LE 2005. With the former, everything works just fine, whereas the later will access the internet only with apps that do not use IPV6 (I've had to deactivate in firefox - but not if I wanted to reach the router config page). It also appears to be somewhat slow, but it might be just me.

I've tried to setup a shared folder (the folder is on A, to be reached by B) either through NFS or Samba, but no luck. When I explore the network, nothing appears as a NFS shared folder. If I do it with Samba, it does appear, and I can set everything up; but I can't mount it. If I try it as a user (which I authorised), I get :

ERROR: Unable to open credentials file!

And if I do it as root, I have :

Error connecting to 82.101.8.42 (Connection refused)
1943: Connection to A failed
SMB connection failed


So it appears that for some reason ( I'm guessing the router is somehow at fault), the samba request gets redirected to this address (which I don't know, though I may ping).

If anybody has any insight ?..

Well, assuming both of your computer are on a local network, why do you want to access your share trought the internet (82.101.8.42 is a "public" internet address)?
A LOT of ISP are blocking Samba port in order to protect their customer against cracker and worms. Sharing your hdd over the net is NOT a good idea... Still, if you want to do so (and become eventually a warez server full of worms) remember you have to edit your /etc/samba/smb.conf to accept connection from the internet (there is a line "allow host"), this is obliviously not permitted by default.

About NFS. NFS uses senseless bloated middle-age communication, openning random port of both side (client and server) and it handles NATing very bad. Long ago, there was an option in NFS that would allow you to share over the web (web or net? dont remember) but this was know to be really broken and unsafe. I haven't heard from it since a loong time, I doubt you want to use it (but you could probably find some old documentation about it).

Actually, I don't want to share through the internet. The thing is, for some reason one of the computers ( client ? server ?) tries to find this credential file by going to this address. I have no idea why.

I suppose the router has some responsabilities in this, but there were a way to explicitely tell samba where to look for it (I've yet to find anything sifting throuht the doc).

why dont you just use your internal ip address (the 192.168.xx or the 10.x.x.x ranges) instead of a hostname (assuming you use hostname)?

I don't. That is the problem.

eh?
well, then use internal (private) ip address? Dont your interfaces already have one? You can use DSL even if your network card don't have ip (the public "internet" ip is assigned to a "fake" interface called ppp0 usually), but it's usually a good idea to set one anyways, as in that case you will need it.
To show your network configuration, type : /sbin/ifconfig. If you want to change it on the fly, try /sbin/ifconfig eth0 192.168.0.X (or whatever ip you want to use) at root. But these change will vanish at reboot, if you don't want to set it each time you boot up, you have to set it "somewhere" (where "somewhere" depend on your distro... I don't know Mandriva at all but there should be some kind of wizard to set it up... in worst case I can point you some "generic" location)

The problem is probably not at your part, but at your provider.
If you ping an unknow domain, you'd got that again (82.x.x.x address) given by your provider DNS ?
I have the same on a mail server, correctly configured, just used locally, not using samba. Something wrong happens with names resolution in postfix and gets this buggy IP address.
My solution was to tune the name resolution by finding first what wrong name was asked (local.local in my case) and putting it in the /etc/hosts file with a 127.0.0.1 address.
Additionally, may I suggest to Half_Elf to read what is exposed before to answer beside ?
So long,
jm

Let's try to get things clear...

Internet connection is handled by the dsl router, which does nat, so internal machines are just connected via lan, with the router acting as gateway.

So each client in the internal network has a private ip (10.x.x.x or 192.168.x.x).

Let's say computer A has ip 192.168.0.2, and computer B has ip 192.168.0.3, and the router has ip 192.168.0.1

Now assuming you've set up the samba server correctly on computer A, you should be able to connect to 192.168.0.2 from computer B. Try the command
and that should be it, right?i'm assuming a lot in the stuff above, but it should help point out where the problem lies. you can tell us where this scenario is different from yours.