On multihoming when server is binded to ipv4 and ipv6 and client sctp init come from ipv6 address in INIT_ACK server is not responding back with ipv4 associations.

[ashisays]

started server using this command ;
sctp_darn -P 4444 -l -H 2::2 -B 1::1 -B 172.16.0.155

connected using this on ipv4, all association is going.
sctp_darn -p 4444 -s -H 172.16.0.185 -c 172.16.0.155
connected using this on IPv6, only v6 associations is going.
sctp_darn -p 4444 -s -H 5::5 -c 1::1

[aaronmdjones]

Possibly related:

https://marc.info/?l=linux-sctp&m=165684809726472&w=2