This section describes parameters specific to the UDP protocol.
Controls the time to live (TTL) value in the IPv4 header for outbound UDP messages sent over IPv4. For more information, see the description for ttl (IPv4).
64 bytes
1 to 255
Yes
Do not change this value in a normal network environment.
Unstable
Sets the value of the hop limit in the IPv6 header for the outbound UDP messages sent over IPv6. For more information, see the description for hoplimit (IPv6).
60
1 to 255
Yes
Do not change this value in a normal network environment.
Unstable
This parameter controls the largest port number UDP can select as an ephemeral port. An application can use an ephemeral port when it creates a connection with a specified protocol but not a port number. Ephemeral ports are not associated with a specific application. When the connection is closed, the port number can be reused by a different application.
Port number
65,535
32,768 to 65,535
Yes
When a larger ephemeral port range is required.
Stable
Defines the maximum send and receive buffer size for a UDP socket. It controls how large the send and receive buffers might be set to by an application that uses setsockopt().
2,097,152
65,536 to 1,073,741,824
Yes
Increase the value of this parameter to match the network link speed if associations are being made in a high-speed network environment.
Stable
Defines the default receive buffer size for a UDP socket. For more information, see max_buf.
57,344 bytes
128 to the current value of max_buf
Yes
Note that an application can use setsockopt (SO_RCVBUF) to change the size for an individual socket. In general, you do not need to change the default value.
able
Defines the default send buffer size for a UDP socket. For more information, see max_buf.
57,344 bytes
1,024 to the current value of max_buf
Yes
Note that an application can use setsockopt (SO_SNDBUF) to change the size for an individual socket. In general, you do not need to change the default value.
Stable
This parameter controls the smallest port number UDP can select as an ephemeral port. An application can use an ephemeral port when it creates a connection with a specified protocol but not a port number. Ephemeral ports are not associated with a specific application. When the connection is closed, the port number can be reused by a different application.
Port number
32,768
1,024 to 65,535
Yes
When a larger ephemeral port range is required.
Stable