Has anyone done any estimates on how much net-wide traffic is useless netbios udp? Are there any suggestions for cutting large chunks of this out of my network without punishing SAMBA and other users who need it?
At 02:59 PM 9/2/98 -0600, Pete Ashdown wrote:
Has anyone done any estimates on how much net-wide traffic is useless netbios udp?
No. But then again, theres a lot of useless traffic, i.e. Phlegm-ings rants currently on the ietf list (at least he's not on NANOG, whew)
Are there any suggestions for cutting large chunks of this out of my network without punishing SAMBA and other users who need it?
1. Implement WINS within the organization and set the netbios node type to h node (0x8) This will force the netbios stack to use a wins lookup and then a lookup via broadcast. 2. Implement WINS within the organization and set the netbios node type to p node (0x4?) This forces the client to ONLY use the WINS server. Note every server has to be registered in the wins database. Neither of these affect DNS resolution. Also, try blocking udp and tcp ports 137, 138 and 139 at your borders. Wins, properly implemented, can eliminate about 90%+ of useless name resolution traffic. Anxiously waiting for Fraziers Linux response :) Eric ========================================================================== Eric Germann CCTec ekgermann@cctec.com Van Wert, OH 45891 http://www.cctec.com Ph: 419 968 2640 Fax: 419 968 2641 Network Design, Connectivity & System Integration Services A Microsoft Solution Provider
On Thu, 3 Sep 1998, Eric Germann wrote:
1. Implement WINS within the organization and set the netbios node type to h node (0x8) This will force the netbios stack to use a wins lookup and then a lookup via broadcast. 2. Implement WINS within the organization and set the netbios node type to p node (0x4?) This forces the client to ONLY use the WINS server. Note every server has to be registered in the wins database.
Neither of these affect DNS resolution.
Also, try blocking udp and tcp ports 137, 138 and 139 at your borders. Wins, properly implemented, can eliminate about 90%+ of useless name resolution traffic.
These are all very good suggestions. Blocking 137/udp, 138/udp, and 139/tcp is a very good idea if you can afford to do that. At a minimum, one should block 137/udp at your border's egress and here is one compelling reason why: There is a very popular WWW log analysis program by the name of WebTrends. It is run on a Win32 platform and when processing GIGs of www access-logs, it will uni-cast for WINS resolution to every foreign IP if finds for WINS name resolution, fail, and then use DNS for resolution. My fear (uneducated on the matter) is that it is not WebTrends but Microsoft's gethostbyaddr() call which would mean that this type of crazy 137/udp WINS resolution traffic is more commonly mis-used than we think. -Tim Keanini %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \ Tim Keanini | "The limits of my language, / / | are the limits of my world." \ \ blast@broder.com | --Ludwig Wittgenstein / \ +================================================/ |Key fingerprint = 7B 68 88 41 A8 74 AB EC F0 37 98 4C 37 F7 40 D6 | / PUB KEY: http://www-swiss.ai.mit.edu/~bal/pks-commands.html \ %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
On Thu, 3 Sep 1998, blast wrote:
There is a very popular WWW log analysis program by the name of WebTrends. It is run on a Win32 platform and when processing GIGs of www access-logs, it will uni-cast for WINS resolution to every foreign IP if finds for WINS name resolution, fail, and then use DNS for resolution.
My fear (uneducated on the matter) is that it is not WebTrends but Microsoft's gethostbyaddr() call which would mean that this type of crazy 137/udp WINS resolution traffic is more commonly mis-used than we think.
I agree. As an ISP, we receive huge amounts of netbios traffic (which is blocked by our acl's and causes our logs to get pretty ugly). The customer pays dearly for this "hack": as the telco bills the customer for every initial connection and also further use. Most single-users get pretty upset when they receive a phone bill of $3000. It's easy to fix if you have the knowledge about how, but most single-users don't. (Port 137 packets denied yesterday: 30000+) Samuel Gunnestad Telenor Nextel -- "If you park, don't drink, accidents cause people." - Confusius
Pete Ashdown wrote:
Has anyone done any estimates on how much net-wide traffic is useless netbios udp? Are there any suggestions for cutting large chunks of this out of my network without punishing SAMBA and other users who need it?
Has anybody done an estimate on how much net-wide traffic is useless ;-) -- Leigh
participants (5)
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blast -
Eric Germann -
Leigh Porter -
Pete Ashdown -
Samuel Gunnestad