---
name: "ip_mreqn"
section: "2type"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ip_mreqn"
---

# ip\_mreqn(2type)

IP multicast request index

## NAME

ip\_mreqn, ip\_mreq - IP multicast request index

## LIBRARY

Standard C library (*libc*)

## SYNOPSIS

```
#include <netinet/in.h>  /* Definition of IP* constants */
```

```
struct ip_mreqn {
    struct in_addr  imr_multiaddr;  /* IP multicast group address */
    struct in_addr  imr_address;    /* IP address of local interface */
    int             imr_ifindex;    /* interface index */
};
```

struct ip\_mreq {\
     struct in\_addr  imr\_multiaddr;  /\* IP multicast group address \*/\
     struct in\_addr  imr\_address;    /\* IP address of local interface \*/ };

## DESCRIPTION

- *.imr\_multiaddr*

  The address of the multicast group the application wants to join or leave. It must be a valid multicast address.

- *.imr\_address*

  The address of the local interface with which the system should join the multicast group; if it is equal to **INADDR\_ANY**, an appropriate interface is chosen by the system.

- *.imr\_ifindex*

  The interface index of the interface that should join/leave the *.imr\_multiaddr* group, or 0 to indicate any interface.

## HISTORY

- *ip\_mreqn*

  Linux 2.2.

- *ip\_mreq*

  Linux 1.2.

## SEE ALSO

[**IP\_ADD\_MEMBERSHIP**(2const)](/IP_ADD_MEMBERSHIP/2const.md), [**IP\_DROP\_MEMBERSHIP**(2const)](/IP_DROP_MEMBERSHIP/2const.md), [**IP\_MULTICAST\_IF**(2const)](/IP_MULTICAST_IF/2const.md), [**ip**(7)](/ip/7.md)