Localhost trouble ?

[vidstige]

Hi,

Being a Mac user I'm not that accomplished with the Unix part.

I have found out that my Mac (G5 2x2 with OS X 10.3.9) regulary tries to open communication with our PC at TCP ports 49xxx (where examples of xxx are 231, 258, 374 ...) with the flag S (doesn't mean anything for me).

At the same time the Mac identifies itself as "dialup18-pi-p2".

So I did dig into the log and found that something/one had changed from localhost to the dialup18. I'm the only one using the Mac and having just one account. So yesterday I did the "sudo" and changed back to localhost. The mac still tried to contact the PC.

After a restart localhost was again changed to dialup18.

Is someone joking with me or do I have an intruder ?

I'm happy for any help.

BR / Christian

[hayne]

1) The name change is just the result of a reverse-lookup on your IP address. I.e. the system asks the DNS server what its name is. I think there have been some articles on the main macosxhints site about configuring the hostname - or maybe I'm just thinking about some forums threads. Anyway, searching will likely find something if you care.

2) The Mac is probably contacting the PC to find out about services that it offers. Do you have any sharing active on the PC?

[giskard22]

To configure the hostname, I think you just put a line in /etc/hostconfig:
HOSTNAME=whatever.domain.com

I wouldn't do this unless you've got a really good reason, though.

Since you have multiple computers, I'm a little surprised this is happening at all. Usually you'd be behind some sort of NAT router, and your internal IP address wouldn't resolve at all. How is this computer connected to the internet?

[vidstige]

Hi,

Ok this proved to be the newbie mixing things up. Thanks for your advices. First searching for hostname found better results then the localhost search I started with.

Secondly your right, I'm connecting to Internet via cable and are sitting behind a router, and that was the error. I had changed to many ip-parameters with no thought on ev consequences.

By reseting our router to default values all problems, incl the strange TCP thing, were gone.

Long time for reply were due to a manual for the router placed on a safe place where I would not forget (remind ?) it.

Again thank you.


BR / Chris