---
name: "rtsol"
section: "8"
platform: "macos"
package: "network_cmds"
version: "741.100.2"
release: "macOS 26.5"
platforms: ["freebsd", "macos"]
url: "https://new.carta.tech/rtsol"
---

# rtsol(8)

router solicitation daemon

## NAME

**rtsold** – router solicitation daemon

## SYNOPSIS

**rtsold** \[**-dDfm1**\] *interface* *...*

**rtsold** \[**-dDfm1**\] **-a**

**rtsol** \[**-dD**\] *interface* *...*

**rtsol** \[**-dD**\] **-a**

## DESCRIPTION

**rtsold** is the daemon program to send ICMPv6 Router Solicitation messages on the specified interfaces. If a node (re)attaches to a link, **rtsold** sends some Router Solicitations on the link destined to the link-local scope all-routers multicast address to discover new routers and to get non link-local addresses.

**rtsold** should be used on IPv6 hosts (non-router nodes) only.

If you invoke the program as **rtsol**, it will transmit probes from the specified *interface*, without becoming a daemon. In other words, **rtsol** behaves as“ **rtsold** **-f1** *interfaces*”.

Specifically, **rtsold** sends at most 3 Router Solicitations on an interface after one of the following events:

- Just after invocation of **rtsold** daemon.

- The interface is up after a temporary interface failure. **rtsold** detects such failures by periodically probing to see if the status of the interface is active or not. Note that some network cards and drivers do not allow the extraction of link state. In such cases, **rtsold** cannot detect the change of the interface status.

- Every 60 seconds if the **-m** option is specified and the **rtsold** daemon cannot get the interface status. This feature does not conform to the IPv6 neighbor discovery specification, but is provided for mobile stations. The default interval for router advertisements, which is on the order of 10 minutes, is slightly long for mobile stations. This feature is provided for such stations so that they can find new routers as soon as possible when they attach to another link.

Once **rtsold** has sent a Router Solicitation, and has received a valid Router Advertisement, it refrains from sending additional solicitations on that interface, until the next time one of the above events occurs.

When sending a Router Solicitation on an interface, **rtsold** includes a Source Link-layer address option if the interface has a link-layer address.

Upon receipt of signal SIGUSR1, **rtsold** will dump the current internal state into */var/run/rtsold.dump*.

## OPTIONS

- **-a**

  Autoprobe outgoing interface. **rtsold** will try to find a non-loopback, non-point-to-point, IPv6-capable interface. If **rtsold** finds multiple interfaces, **rtsold** will exit with error.

- **-d**

  Enable debugging.

- **-D**

  Enable more debugging including the printing of internal timer information.

- **-f**

  **-f** prevents **rtsold** from becoming a daemon (foreground mode). Warning messages are generated to standard error instead of [syslog(3)](/syslog/3.md).

- **-m**

  Enable mobility support. If this option is specified, **rtsold** sends probing packets to default routers that have advertised Router Advertisements when the node (re)attaches to an interface. Moreover, if the option is specified, **rtsold** periodically sends Router Solicitation on an interface that does not support SIOCGIFMEDIA ioctl.

- **-1**

  Perform only one probe. Transmit Router Solicitation packets until at least one valid Router Advertisement packet has arrived on each *interface*, then exit.

## DIAGNOSTICS

The **rtsold** utility exits 0 on success, and \>0 if an error occurs.

## FILES

- */var/run/rtsold.pid*

  the pid of the currently running **rtsold**.

- */var/run/rtsold.dump*

  dumps internal state on.

## SEE ALSO

[rtadvd(8)](/rtadvd/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **rtsold** command is based on the **rtsol** command, which first appeared in WIDE/KAME IPv6 protocol stack kit. **rtsol** is now integrated into [rtsold(8)](/rtsold/8.md).

## BUGS

In some operating systems, when a PCMCIA network card is removed and reinserted, the corresponding interface index is changed. However, **rtsold** assumes such changes will not occur, and always uses the index that it got at invocation. As a result, **rtsold** may not work if you reinsert a network card. In such a case, **rtsold** should be killed and restarted.

The IPv6 autoconfiguration specification assumes a single-interface host. You may see kernel error messages if you try to autoconfigure a host with multiple interfaces. Also, it seems contradictory for **rtsold** to accept multiple *interface* arguments.