Hi,

I am currently modifying the config on a 4232 layer 3 running IOS 12.

I currently have a working config with inter-vlan routing working
fine, but I am now upgrading my DHCP servers and tidying things up,
which means re-configuring the ip helper-address settings.

However, I'm a bit confused by the settings for ip helper-address and
ip forward-protocol.

I want to forward DHCP requests to my DHCP server but I don't want to
forward any other UDP protocols. If I *only* specify  "ip
helper-address x.x.x.x" then some Cisco documentation suggests that
the router only acts as a BOOTP relay agent. 

However, other Cisco documentation suggests that it also enables
forwarding for other UDP protocols, such as NETBIOS.

I already have something similar to the following in the interface
settings:

interface GigabitEthernet3.14
 encapsulation dot1Q 50
 ip address 192.168.50.1 255.255.255.0
 ip helper-address 192.168.1.68
 no ip redirects
 no ip directed-broadcast

Do I need to specify something like

  no ip forward-protocol udp netbios-ns
  no ip forward-protocol udp netbios-dgm

....in the global settings or is that redundant?

Any help appreciated!

Kris Shaw.

Kris Shaw <8bkoay002@sneakemail.com> wrote in message news:<t68g80lvdaltg2q7vr1pb3r2ddhlp18rgh@4ax.com>...
> I want to forward DHCP requests to my DHCP server but I don't want to
> forward any other UDP protocols. If I *only* specify  "ip
> helper-address x.x.x.x" then some Cisco documentation suggests that
> the router only acts as a BOOTP relay agent. 
> 
> However, other Cisco documentation suggests that it also enables
> forwarding for other UDP protocols, such as NETBIOS.

Any of these might help ...

no ip forward-protocol udp tftp

no ip forward-protocol udp dns

no ip forward-protocol udp time

no ip forward-protocol udp netbios-ns

no ip forward-protocol udp netbios-dgm

no ip forward-protocol udp tacacs

ip forward-protocol udp bootpc

Rgrds
Rahul Sawarkar

On 22 Apr 2004 20:49:22 -0700, torahuls@vsnl.com (rowl) said to us:

....
>> 
>> However, other Cisco documentation suggests that it also enables
>> forwarding for other UDP protocols, such as NETBIOS.
>
>Any of these might help ...
>
>no ip forward-protocol udp tftp
....
>Rgrds
>Rahul Sawarkar

Hi,

Thanks for that - will give it a go.

Kris.

Quit simple. Just put the "no ip forward-protocol udp"-commands in.
It won't hurt. You want to block anything anyway. Just let bootp through....

Regards,
Geert

Kris Shaw wrote:

> Hi,
> 
> I am currently modifying the config on a 4232 layer 3 running IOS 12.
> 
> I currently have a working config with inter-vlan routing working
> fine, but I am now upgrading my DHCP servers and tidying things up,
> which means re-configuring the ip helper-address settings.
> 
> However, I'm a bit confused by the settings for ip helper-address and
> ip forward-protocol.
> 
> I want to forward DHCP requests to my DHCP server but I don't want to
> forward any other UDP protocols. If I *only* specify  "ip
> helper-address x.x.x.x" then some Cisco documentation suggests that
> the router only acts as a BOOTP relay agent. 
> 
> However, other Cisco documentation suggests that it also enables
> forwarding for other UDP protocols, such as NETBIOS.
> 
> I already have something similar to the following in the interface
> settings:
> 
> interface GigabitEthernet3.14
>  encapsulation dot1Q 50
>  ip address 192.168.50.1 255.255.255.0
>  ip helper-address 192.168.1.68
>  no ip redirects
>  no ip directed-broadcast
> 
> Do I need to specify something like
> 
>   no ip forward-protocol udp netbios-ns
>   no ip forward-protocol udp netbios-dgm
> 
> ...in the global settings or is that redundant?
> 
> Any help appreciated!
> 
> Kris Shaw.
>