PMTU discovery mechanism on closed UDP socket, no entry added

Hi, When I send UDP packet (too big for whole path) and close socket right after, ICMP Fragmentation Needed packet is ignored (?) and no entry regarding path MTU is created. When process waits before closing socket (about 1s in my case) entry about path MTU is added to routing table. The result

PMTU discovery mechanism on closed UDP socket, no entry added

Hi, When I send UDP packet (too big for whole path) and close socket right after, ICMP Fragmentation Needed packet is ignored (?) and no entry regarding path MTU is created. When process waits before closing socket (about 1s in my case) entry about path MTU is added to routing table. The result