ip_strict_dst_multihoming and ip6_strict_dst_multihoming

Description

Determine whether a packet arriving on a non-forwarding interface can be accepted for an IP address that is not explicitly configured on that interface. If ip_forwarding is enabled, or xxx:ip_forwarding for the appropriate interfaces is enabled, then this parameter is ignored, because the packet is actually forwarded.

Refer to RFC 1122 3.3.2.4.

Default

0 (loose multihoming)

Range

0 = Off (loose multihoming)

1 = On (strict multihoming)

Dynamic?

Yes

When to Change

If a machine has interfaces that cross strict networking domains (for example, a firewall or a VPN node), set this variable to 1.

Commitment Level

Unstable

IP Tunable Parameters With Additional Cautions

Changing the following parameters is not recommended unless there are extenuating circumstances that are described with each parameter.

ip_ire_pathmtu_interval

Description

The interval in milliseconds when IP flushes the path maximum transfer unit (PMTU) discovery information, and tries to rediscover PMTU.

Refer to RFC 1191 on PMTU discovery.

Default

10 minutes

Range

5 seconds to 277 hours

Dynamic?

Yes

When to Change

Do not change this value.

Commitment Level

Unstable

ip_icmp_return_data_bytes and ip6_icmp_return_data_bytes

Description

When IPv4 or IPv6 sends an ICMPv4 or ICMPv6 error message, it includes the IP header of the packet that causes the error message. This parameter controls how many extra bytes of the packet beyond the IPv4 or IPv6 header to be included in the ICMPv4 or ICMPv6 error message.

Default

64 bytes

Range

8 to 65,536 bytes

Dynamic?

Yes

When to Change

Do not change the value. Including more information in an ICMP error message might help in diagnosing network problems. If this feature is needed, increase the value.

Commitment Level

Unstable