maskreply(1Mtcp)

maskreply -- send gratuitous ICMP mask reply

Synopsis

maskreply

Description

maskreply checks the kernel variable icmp_answermask; if it is set, then for each interface maskreply sends an unsolicited ICMP netmask reply to the address returned by SIOCGIFBRDADDR using the netmask returned by SIOCGIFNETMASK. maskreply will send a mask reply out an interface only if all of the following are true: the interface is in address family AF_INET, the interface is up, the interface supports broadcasts, and the interface is not point-to-point.

A host that acts as an authority for netmasks is required by RFC 1122 to broadcast an ICMP subnetmask reply when the host comes up. This requirement can be satisfied by executing maskreply in /etc/inet/config.

References

config(4tcp), icmp(7tcp), ifconfig(1Mtcp), ip(7tcp)

RFC 792, RFC 1122