multiple interfaces

Stephen Langasek vorlon at
Thu Sep 9 05:55:19 GMT 1999

On Thu, 9 Sep 1999 Chris Watt <cnww at> wrote:

> At 04:05 PM 9/8/99 +1000, Tom Priore wrote:
> >I'm having a problem getting samba to work on 2 interfaces
> >I have a machine set up with 2 nics. It is a red hat linux 6.0 computer
> >running samba 2.0.5a. The machine is set up as a firewall so that the
> >computers on the local side are protected from all those evil people on the
> >@home network:)

> Every cable ISP I know of blocks the ports used by smb in order to protect
> their users. Many (possibly even most) Windows installations would
> otherwise be totally vulnerable to anybody who wanted to mess around with
> the machine (e.g. Half the systems that I see have been installed with
> remote administration enabled, no password (because the user doesn't want
> to enter one to login), and TCP/IP up and running). I'd suggest the first
> thing to do would be to get in touch with one of the tech people at your
> ISP, not to be confused with "tech support" ;), and find out what ports
> they are blocking. Security concerns aside many ISPs would probably want to
> block smb ports just to avoid all that traffic M$ boxes generate while
> trying to find each other.

This is interesting.  I've never had difficulty reaching Samba servers
running off of cable modems.  Nor have I ever seen a cable provider do
anything in the interest of protecting their users. :)
The quickest test for whether or not the port is being blocked is to try to
telnet to port 139 on the host from a remote location.

And SMB doesn't really generate all that much traffic from an ISP's point of
view.  The messiest part of the protocol involves broadcast traffic, which
doesn't work with most dialup setups anyway.

-Steve Langasek
postmodern programmer

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