NAT Logs

[michmoor]

@mcury

Its already parsed for me

[mcury]

@michmoor

So you got it.
Weird, I don't have those here.. Any tip of what I should do ?

[michmoor]

@mcury Graylog did it for me. For the input i selected IPFIX UDP

[mcury]

@michmoor said in NAT Logs:

@mcury Graylog did it for me. For the input i selected IPFIX UDP

Also using that input.

Did you enable tracking on the firewall rule that is associated with the NAT rule ?

Ohh, disregard that.
It is working here..

[michmoor]

@mcury The only piece i dont know how to do is actually display data to show top talkers.
each IPfix record shows bytes which is great but i would like a table that shows all the fields plus the amount of data seen cumulative.

[mcury]

@michmoor said in NAT Logs:

The only piece i dont know how to do is actually display data to show top talkers.
each IPfix record shows bytes which is great but i would like a table that shows all the fields plus the amount of data seen cumulative.

hmm, as I see it, you would nee to create a widget with the search field:

Example if the destination host is in the 192.168.255.0/24 subnet.
postNATSourceIPv4Address:192.168.255.* OR postNATDestinationIPv4Address:192.168.255.*

Then, as per picture above, filter by destination or source (this will give you the external users data), use SUM and Data Table.

[michmoor]

@mcury Ok yeah thats the way to go BUT....i have to use NetFlow as netflow already has bytes parsed in the output while IPFix does not.

Still figuring out how to normalize the nf_bytes column to megabytes

[mcury]

@michmoor said in NAT Logs:

Still figuring out how to normalize the nf_bytes column to megabytes

Try this pipeline rule:

rule "arithmetic"
when
has_field("octetDeltaCount")
then
let size_kb = to_double($message.octetDeltaCount);
set_field("size_bytes", size_kb / to_double(value:"1048576"));
end

This will give you something like this:

[michmoor]

@mcury Not sure if its working to be honest.
There are no errors showing up in the pipeline so messages are being processed.

Message:

[mcury]

@michmoor said in NAT Logs:

@mcury Not sure if its working to be honest.
There are no errors showing up in the pipeline so messages are being processed.

Did you edit the pipeline connections and assigned to the ipfix stream ?

[michmoor]

@mcury
Im on Graylog 6.0.5

Yes my pipeline is connected to my stream. Im using Netflow data just for testing.

[mcury]

@michmoor I'm on Graylog 6.1.5, but it should work on 6.0.5, no problems with that.

Is Configurations tab, Manage processors, is pipeline active ?

[michmoor]

@mcury
Yep its active.
I have other pipelines in effect so this is all working. The new pipeline for Netflow is the latest addition. I guess I'm trying to figure out how to prove its working
With my other pipelines, I'm extracting fields into Grok Patterns so i can tell immediately if its working.

Considering i see no errors in the pipeline i have to imagine its working.

[mcury]

@michmoor said in NAT Logs:

Considering i see no errors in the pipeline i have to imagine its working.

But do you see messages being processed in the Throughput ?

[michmoor]

@mcury

[mcury]

@michmoor said in NAT Logs:

@mcury

Now, check if the field exists:

[michmoor]

@mcury

It does. I feel like we are getting close to a confirmation. LOL

Is my pipeline rule correct?

[mcury]

@michmoor said in NAT Logs:

It does. I feel like we are getting close to a confirmation. LOL

So, the rule is processing the data, and the field exists.
It must be showing up in the logs..

@michmoor said in NAT Logs:

Is my pipeline rule correct?

That is an old rule, I'm using now octetDeltaCount, replace the rule with the one I posted above.

After that, go to rule simulator, JSON, paste the example below, then click in run rule simulator, and check if the field size_bytes will appear

{
  "destinationTransportPort": 3246,
  "size_bytes": 0,
  "gl2_remote_ip": "192.168.255.249",
  "gl2_remote_port": 20815,
  "sourceIPv4Address": "192.168.255.249",
  "source": "192.168.255.249",
  "ipClassOfService": 0,
  "gl2_source_input": "6627f43d99aaec416300cd0e",
  "hostname_src": "pfsense.home.arpa.",
  "egressInterface": 1,
  "octetDeltaCount": 168,
  "gl2_source_node": "0f929def-42b9-4ea6-8980-799a62f7bdb3",
  "sourceTransportPort": 3246,
  "flowEndMilliseconds": "2024-04-23T20:21:02.098Z",
  "timestamp": "2024-04-23T20:21:24.000Z",
  "destinationIPv4Address": "192.168.255.253",
  "gl2_accounted_message_size": 575,
  "streams": [
    "63fe3ab48b6393126ef3c2f7"
  ],
  "gl2_message_id": "01HW69XJD000004NFV0XGMQ27B",
  "message": "Ipfix [192.168.255.249]:3246 <> [192.168.255.253]:3246 proto:1 pkts:2 bytes:168",
  "ingressInterface": 1,
  "packetDeltaCount": 2,
  "protocolIdentifier": 1,
  "hostname_dst": "rpi4.home.arpa.",
  "_id": "0ea147d7-01af-11ef-8e3e-dca632a54719",
  "flowStartMilliseconds": "2024-04-23T20:21:01.096Z"
}

[michmoor]

@mcury Rule simulation returns without a problem

So I'm a bit confused as to how you figured out there was a field called "size_bytes" as that does not come up for me when i review the available fields. In fact, unlike NetFlow which has a field called "nf_bytes" there is nothing similar in IPFix within Graylog.

[mcury]

@michmoor said in NAT Logs:

@mcury Rule simulation returns without a problem

So I'm a bit confused as to how you figured out there was a field called "size_bytes" as that does not come up for me when i review the available fields. In fact, unlike NetFlow which has a field called "nf_bytes" there is nothing similar in IPFix within Graylog.

I'm using IPFIX UDP, the rule "arithmetic" above reflects that.

The size_bytes field is the one we are creating with the pipeline.
I'm transforming the field octetDeltaCount, which is in bytes, to size_bytes , which is in megabytes.