topic ASA Netbios Broadcast traffic dropped INSIDE in Network Security

ASA Netbios Broadcast traffic dropped INSIDE

jaysin144 — Tue, 12 Mar 2019 01:53:53 GMT

I have an ASA that keeps dropping what looks like Netbios Boradcast packets on the inside interface.

06-06-2013 13:42:44 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.134/137 to inside:10.1.1.255/137

06-06-2013 13:42:44 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.214/137 to inside:10.1.1.255/137

06-06-2013 13:42:43 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.214/137 to inside:10.1.1.255/137

06-06-2013 13:42:42 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.214/137 to inside:10.1.1.255/137

06-06-2013 13:42:41 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.214/137 to inside:10.1.1.255/137

06-06-2013 13:42:40 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.214/137 to inside:10.1.1.255/137

06-06-2013 13:42:38 Local4.Debug 10.1.1.247 %ASA-7-710005: UDP request discarded from 10.1.1.16/137 to inside:10.1.1.255/137

Both IP's are on the inside network. Any idea why and how I can allow this broadcast traffic? Everything else, including IPSEC VPN's look good.

ASA Netbios Broadcast traffic dropped INSIDE

Julio Carvajal — Thu, 06 Jun 2013 17:44:52 GMT

Hello Jason,

As you said it, this traffic is on the same LAN, as it's a broadcast it will reach the ASA, but there is not need to allow it trough the ASA as this is a directed broadcast (directed to the 10.1.1.0/24 broadcast address)

The hosts will still get it.,

Do you follow me,

ASA Netbios Broadcast traffic dropped INSIDE

jaysin144 — Thu, 06 Jun 2013 17:48:38 GMT

I follow, but if it's a directed broadcast, why would it be hitting the inside interface of this firewall? Is it possible there's an issue someone else thats forwarding these directed packets here? Is this just a non issue? SHould i just filter %ASA-7-710005 from the logs and be done with it?

ASA Netbios Broadcast traffic dropped INSIDE

Julio Carvajal — Thu, 06 Jun 2013 17:58:41 GMT

Hello Jason,

All of the devices are on the same , including the ASA,

It's expected to received it, The ASA as a security device will drop it,

Expected behavior with Netbios,

No need to worry

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