Hello @TRACY HARTMANN ,
easy part :
>> Also not sure why the 172.17.0.0 won't take the subnet of /16
because 172.17.0.0/16 is a Class B network that it is the default network mask so it is not shown in configuration
difficult part :
>>neighbor 10.3.72.6 remote-as 64538
>> neighbor 10.3.72.22 remote-as 64539
you have two eBGP sessions in addition to the local prefixes injected by network command your router is allowed to send to neighbor A what it has received by neighbor B and viceversa. They also use different private AS numbers and this can make accept some unwanted route.
all you need is to use a concept called filtering by As-path
all local routes have AS path empty before sending
ip as-path access-list 11 permit ^$
the regular expression ^$ means an empty AS path string ""
then in BGP you add
neighbor 10.3.72.6 filter-list 11 out
neighbor 10.3.72.22 filter-list 11 out
and this should fix your issue as only local routes are advertised in all cases even if one neighbor withdrawn a remote prefix
The filter-list uses the configured as-path access-list 11 to allow only locally originated routes to be sent to each eBGP neighbor.
Hope to help
Giuseppe
