---
title: "swx-tcpdump"
slug: "swx-tcp-dump"
updated: 2025-10-21T18:39:42Z
published: 2025-10-21T18:39:42Z
canonical: "docs.swxtch.io/swx-tcp-dump"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.swxtch.io/llms.txt
> Use this file to discover all available pages before exploring further.

# swx-tcpdump

WHAT TO EXPECT

Users on Linux can use a cloudSwXtch-specific version of tcpdump called `swx-tcpcump`. This tool helps with capturing multicast packets sent to and from the cloudSwXtch. It is the same as `tcpdump`, but with logic to decode our own header and display the original multicast payload.

  

**In this article,** users will learn about the available arguments for swx-tcpdump.

### Using swx-tcpdump

Execute the following command:

```shell
swx-tcpdump
```

> [!NOTE]
> **NOTE**
> 
> The default interface is **swx0** (used with xNIC Type 1 and 3). If the multicast is running on a different interface, then the user will need to specify that interface. To get a list of interfaces you can use `ip a`. After you get the name of the correct interface, you can use the `-i` argument followed by your desired interface name.

**Example**:

```shell
swx-tcpdump -i ens6
```

#### Additional arguments

Users can use the **-h** argument, as shown below, to get a list of available arguments for swx-tcpdump.

```shell
$ swx-tcpdump -h
swx-tcpdump version 5.0.0-PRE-GIT
libpcap version 1.10.4 (with TPACKET_V3)
OpenSSL 3.0.13 30 Jan 2024
Usage: swx-tcpdump [-AbdDefhHIJKlLnNOpqStuUvxX#] [ -B size ] [ -c count ] [--count]
                [ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ]
                [ -i interface ] [ --immediate-mode ] [ -j tstamptype ]
                [ -M secret ] [ --number ] [ --print ]
                [ --print-sampling nth ] [ -Q in|out|inout ] [ -r file ]
                [ -s snaplen ] [ -T type ] [ --version ]
                [ -V file ] [ -w file ] [ -W filecount ] [ -y datalinktype ]
                [ --time-stamp-precision precision ] [ --micro ] [ --nano ]
                [ -z postrotate-command ] [ -Z user ] [ expression ]
```

Users can see the man page of the [original tcpdump page](https://www.tcpdump.org/manpages/tcpdump.1.html).