Outbound Netbios Connection

Outbound Netbios Connection

Post by Robert Conno » Wed, 09 Jan 2002 02:36:36



After receiving some emails my exchange server attempts to make a connection
to the sending email server on port 137.  I have my firewall configured to
block all outbound traffic except on four or five ports.  Is there any
benefit to me for my server responding to the email with the connection?
Should I be allowing outbound port 137 connections?

Thanks,

Robert

 
 
 

Outbound Netbios Connection

Post by Rich Matheisen [MVP » Wed, 09 Jan 2002 10:44:03



>After receiving some emails my exchange server attempts to make a connection
>to the sending email server on port 137.  I have my firewall configured to
>block all outbound traffic except on four or five ports.  Is there any
>benefit to me for my server responding to the email with the connection?

None. Don't allow port 137 into, or out of, your network.

Quote:>Should I be allowing outbound port 137 connections?

Nope.

Exchange, being a Windows application, feels compelled to use NetBIOS.
If the other end of the connection is another Exchange server on your
own network this might be okay, but not to another Exchange server on
sombody else's netork!

--
Rich Matheisen
MCSE+I, Exchange MVP
MS Exchange FAQ at http://www.swinc.com/resource/exch_faq.htm

 
 
 

Outbound Netbios Connection

Post by Robert Conno » Thu, 10 Jan 2002 01:11:34


Rich,

Thanks.  I will keep the settings that I have.

Robert




> >After receiving some emails my exchange server attempts to make a
connection
> >to the sending email server on port 137.  I have my firewall configured
to
> >block all outbound traffic except on four or five ports.  Is there any
> >benefit to me for my server responding to the email with the connection?

> None. Don't allow port 137 into, or out of, your network.

> >Should I be allowing outbound port 137 connections?

> Nope.

> Exchange, being a Windows application, feels compelled to use NetBIOS.
> If the other end of the connection is another Exchange server on your
> own network this might be okay, but not to another Exchange server on
> sombody else's netork!

> --
> Rich Matheisen
> MCSE+I, Exchange MVP
> MS Exchange FAQ at http://www.swinc.com/resource/exch_faq.htm

 
 
 

1. SMTP Virtual Server Properties... Outbound Connections

When I attempt to open the Outbound Connections in the Default SMTP
Virtual Server Properties I get the following error: please ensure
that the outgoing connections limit is greater than or equal to the
per domain outgoing connections limit.  I does not let me in to change
the connection limits.  Any suggestions? Exchange 2000 SP3 / Windows
2000 SP3.

2. exchange schema

3. Outbound Connections configuration

4. ILS SERVER

5. AMMENDMENT: Outbound Connections configuration

6. Message Stuck in MTS-OUT

7. Remote Connection & Outbound Queue..ATT: Kirill

8. Deploying Outlook 2000

9. IMC Outbound connections.

10. Secure Outbound SMTP connections

11. Outbound connections

12. Outbound SMTP with dialup connection

13. SMTP outbound connection hangs after applying MS02-025