I am seen funny behaviour with synchronization in bgp. sometimes when i turn synchronisation off and advertise prefixes through network statement and my IGP (OSPF) doesn't have those routes, BGP refuses to advertise the prefixes. sometimes, it does (regardless of the prefix being in IGP or not.
I know no synchronization is meant to disable the prefix check in the routing table and should allow BGP advetise prefixes.
I am advertising to an ebgp neighbour.
pls enlighten me on what is happening. could it be the IOS version?