System Administration Guide: Network Services

Configuring the net.slp.interfaces Property

If the net.slp.interfaces property is set, slpd listens for unicast and multicast/broadcast SLP requests on the interfaces that are listed in the property, rather than on the default interface.

Usually, you set the net.slp.interfaces property in conjunction with enabling broadcast by setting the net.slp.isBroadcastOnly property, because multicast has not been deployed in the network. However, if multicast has been deployed, but is not being routed on this particular multihomed host, a multicast request can arrive at slpd from more than one interface. This situation can occur when the routing of packets is handled by another multihomed host or router that connects the subnets that are served by the interfaces.

When such a situation occurs, the SA server or the UA that is sending the request receives two responses from slpd on the multihomed host. The responses are then filtered by the client libraries and the client does not see them. The responses are, however, visible in the snoop trace.

Note –

If unicast routing is turned off, services that are advertised by SA clients on multihomed hosts might not be reachable from all the subnets. If services are unreachable, SA clients can do the following:

The SA client library makes no effort to assure that reachable URLs are advertised. The service program, which might or might not handle a multihomed host with no routing, is then responsible for assuring that reachable URLs are advertised.

Before you deploy a service on a multihomed host with unicast routing disabled, use snoop to determine whether the service handles requests from multiple subnets correctly. Furthermore, if you plan to deploy a DA on the multihomed host, see DA Placement and Scope Name Assignment.

ProcedureHow to Configure the net.slp.interfaces Property

Use the following procedure to change the net.slp.interfaces property in the slp.conf file.

  1. Become superuser or assume an equivalent role.

    Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

  2. Stop slpd and all SLP activity on the host.

    # svcadm disable network/slp
  3. Back up the default /etc/inet/slp.conf file before you change the configuration settings.

  4. Change the net.slp.interfaces property in the slpd.conf file:


    List of IPv4 addresses or host names of the network interface cards on which the DA or SA should listen for multicast, unicast UDP, and TCP messages on port 427

    For example, a server with three network cards and multicast routing that is turned off is connected to three subnets. The IP addresses of the three network interfaces are,, and The subnet mask is The following property setting causes slpd to listen on all three interfaces for unicast and multicast/broadcast messaging:


    Note –

    You can specify IP addresses or resolvable host names for the net.slp.interfaces property.

  5. Save your changes and close the file.

  6. Restart slpd to activate your changes.

    # svcadm enable network/slp