zone tranfer denied

Apr 7 01:29:29 ns1 named[72]: client 206.228.179.10#40953: zone transfer
'mydomain.com/IN' denied
Apr 7 01:40:17 ns1 named[72]: client 144.228.254.10#56920: zone transfer
'mydomain.com/IN' denied
Apr 7 01:56:07 ns1 named[72]: client 144.228.255.10#34335: zone transfer
'mydomain.com/IN' denied

Is this mean that my provider (Sprint) is trying to update their DNS server
from mine? They are our secondary, so I should allow the transfer? But
then, do I have to add their IP to all of my zone records? i.e.

zone "1.yy.xx.in-addr.arpa" {
type master;
file "isot-xx.yy.1.rev";
allow-query { any; };
allow-transfer {
internals;
206.228.179.10;
144.228.254.10;
144.228.255.10;
};
};

zone "2.yy.xx.in-addr.arpa" {
type master;
file "isot-xx.yy.2.rev";
allow-query { any; };
allow-transfer {
internals;
206.228.179.10;
144.228.254.10;
144.228.255.10;
};
};

and on and on?