Access-lists ?

it_amaan · 04-08-2008, 11:31 PM

Hi,

I need some details regarding access-lists in particular with protocol parameter.
In some cases, for denying a host it is used as ip while in other it is as tcp/udp.
what must be actually used for denying a host and a network?

Also, see the below lists;

access-list 101 deny udp any any eq netbios-ns log
access-list 101 deny udp any any eq netbios-dgm log

Pls explain about the port nos used here.
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**Cellus** · 04-10-2008, 03:28 PM

With an extended access list, you can either define the port with either the popular service name (eg. www) or by the port number (eg. 80). For example for the value netbios-ns you can instead use 137 (its port number). This is mainly for convenience and makes it more human readable.

Keep in mind packets can be commonly sent via TCP or UDP, and as such the rules are granular enough to recognize and work with either.

04-08-2008, 11:31 PM	#1 (permalink)
it_amaan Registered User Join Date: Mar 2008 Posts: 5 OS: winxp sp2	Access-lists ? Hi, I need some details regarding access-lists in particular with protocol parameter. In some cases, for denying a host it is used as ip while in other it is as tcp/udp. what must be actually used for denying a host and a network? Also, see the below lists; access-list 101 deny udp any any eq netbios-ns log access-list 101 deny udp any any eq netbios-dgm log Pls explain about the port nos used here. Reply With Quote

04-10-2008, 03:28 PM	#2 (permalink)
Cellus Moderator Networking Team Join Date: Aug 2006 Location: Canada Posts: 2,499 OS: Windows Vista Business SP1 My System	Re: Access-lists ? With an extended access list, you can either define the port with either the popular service name (eg. www) or by the port number (eg. 80). For example for the value netbios-ns you can instead use 137 (its port number). This is mainly for convenience and makes it more human readable. Keep in mind packets can be commonly sent via TCP or UDP, and as such the rules are granular enough to recognize and work with either. __________________ TSF Networking Team HijackThis 5 Step Process Donate!