tmnxMobPdnApnPcoDnsV4SecAddr 1.3.6.1.4.1.6527.3.1.2.71.1.10.1.21

The value of tmnxMobPdnApnPcoDnsV4SecAddr specifies the IPv4 address of the secondary DNS server used by a User Equipment (UE) to resolve domain names to IP addresses.