Solved

What is "ip forward-protocol udp netbios-ss"

Posted on 2007-04-03
3
3,199 Views
Last Modified: 2009-07-29
I have this command listed on the configuration of our Cisco 4507R layer 3 switch.
"ip forward-protocol udp netbios-ss"
What exactly does this do?
0
Comment
Question by:Spelurker
  • 2
3 Comments
 
LVL 3

Accepted Solution

by:
Bobby_Thekkekandam earned 500 total points
ID: 18844968
Very simply put, "ip forward-protocol udp netbios-ss" enabled forwarding of netbios session service (port 139) broadcast packets for interfaces configured with an ip helper.

To provide a more detailed explanation, the ip forward-protocol global configuration command combined with the ip helper-address command allows you to control which broadcast packets and whichi protocols are forwarded. If you use the ip forward-protocol command, specifying only UDP without the port enables forwarding and flooding on the default ports (TFTP, DNS, Time, NetBIOS name server, NetBIOS datagram server, BOOTP, TACACS).

So specifying netbios-ss explicitly makes the 4507 forward any NetBIOS session service broadcast packets.

Hope that helps,

Bobby
0
 

Author Comment

by:Spelurker
ID: 18845039
Bobby,
I do have the ip helper-address command listed for several of my internal VLANs. As I understand it, that points machines to the ip address of a DHCP server on another subnet or VLAN. If I remove the "ip forward-protocol udp netbios-ss" command, will that screw up the ability to retrieve DHCP for those VLANs or merely stop these 'netbios' broadcasts?
Thanks.
0
 
LVL 3

Expert Comment

by:Bobby_Thekkekandam
ID: 18845088
Hi,

removing netbios-ss forwarding will only stop the forwarding of NetBIOS broadcasts. It will not affect DHCP.

HTH,

Bobby
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Join & Write a Comment

I eventually solved a perplexing problem setting up telnet for a new switch.  I installed a new Cisco WS-03560X-24P switch connected to an existing Cisco 4506 running a WS-X4013-10GE Sup II-Plus. After configuring vlans and trunking,  I could no…
Quality of Service (QoS) options are nearly endless when it comes to networks today. This article is merely one example of how it can be handled in a hub-n-spoke design using a 3-tier configuration.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

760 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

21 Experts available now in Live!

Get 1:1 Help Now