---
name: "udpxrec"
section: "1"
platform: "linux"
package: "udpxy"
version: "1.0.25.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/udpxrec"
---

# udpxrec(1)

a programmable multicast traffic recording utility.

## NAME

udpxrec - a programmable multicast traffic recording utility.

## SYNOPSIS

**udpxrec** \[-v\] \[-b *\<begin\_time\>*\] \[-e *\<end\_time\>*\] \[-M *\<maxfilesize\>*\] \[-p *\<pidfile\>*\] \[-B *\<bufsizeK\>*\] \[-n *\<nice\_incr\>*\] \[-u *\<seconds\_to\_wait\>*\] \[-m *\<mcast\_ifc\_addr\>*\] \[-l *\<logfile\>*\] -c *\<src\_addr\>*:*\<port\>* *\<dstfile\>*

## DESCRIPTION

udpxrec is a utility designed to record (save into a disk file) a segment of multicast network traffic; the amount of data saved/recorded could be specified in length (KB) or duration (seconds).

## OPTIONS

udpxrec accepts the following options:

- **-v**

  Enable verbose output \[default = *disabled*\].

- **-T**

  Do NOT run as a daemon \[default = *daemon if root*\].

- **-m *\<mcast\_ifc\_addr\>***

  IPv4 address/interface of (multicast) source \[default = *0.0.0.0*\].

- **-l *\<logfile\>***

  Log output to file \[default = *stderr*\].

- **-n *\<nice\_incr\>***

  Nice value increment \[default = *0*\].

- **-B *\<sizeK\>***

  Buffer size (65536, 32Kb, 1Mb) for inbound (multicast) data \[default = *2048 bytes*\].

- **-R *\<msgs\>***

  Maximum number of messages to buffer (*-1* = *all*) \[default = *1*\].

- **-b *\<begin\_time\>***

  Begin recording at *\[+\]dd:hh24:mi.ss*, '**+**' signifies relative timing (in N hours/min/sec).

- **-e *\<endtime\>***

  Stop recording at *\[+\]dd:hh24:mi.ss*, '**+**' signifies relative timing (in N hours/min/sec).

- **-M *\<maxfilesize\>***

  Maximum size of destination file.

- **-p *\<pidfile\>***

  Pidfile for this process \[**MUST be specified if daemon**\].

- **-u *\<seconds\_to\_wait\>***

  Seconds to wait before updating on how long till recording starts.

## EXAMPLES

**udpxrec -b 15:45.00 -e +2:00.00 -M 1.5Gb -n 2 -B 64K -c 224.0.11.31:5050 /opt/video/tv5.mpg**

Begin recording multicast channel 224.0.11.31:5050 at 15:45 today, finish recording in two hours or if destination file size \>= 1.5 Gb; set socket buffer to 64Kb; increment nice value by 2; write captured video to /opt/video/tv5.mpg.

## AUTHORS

Pavel V. Cherenkov and all the good people who submitted patches or otherwise contributed to the project.

## SEE ALSO

[**udpxy**(1)](/udpxy/1.md)