If you read/see videos about OSPF, it will be said that you can only filter on INBOUND or 1/0 on OUTBOUND (via ip ospf database-filter all out / neighbor x.x.x.x database-filter all out).
You will say to me, no problem I can filter by means of “area range xxxxx not-advertise” (LSA Type 3) or “summary-address xxxx no-advertise” (LSA Type 5).
Ok, now let’s say, I want with distribute-list and ACL, you filter out some routes ?
You could do this as :
R1(config-router)#distribute-list 10 out connected R1(config-router)#do sh run | sec router router ospf 1 router-id 1.1.1.1 no capability transit area 14 nssa summary-address 10.1.4.4 255.255.255.255 not-advertise summary-address 10.22.4.4 255.255.255.255 not-advertise network 10.1.1.1 0.0.0.0 area 0 network 10.1.14.0 0.0.0.255 area 14 network 11.1.1.0 0.0.0.255 area 0 neighbor 11.1.1.2 database-filter all out distribute-list 10 out connected distance 255 9.9.9.9 0.0.0.0 41 R1(config-router)#
And you could do more :
R1(config-router)#distribute-list 10 out ? Async Async interface Auto-Template Auto-Template interface BVI Bridge-Group Virtual Interface CDMA-Ix CDMA Ix interface CTunnel CTunnel interface Dialer Dialer interface Ethernet IEEE 802.3 GMPLS MPLS interface LongReachEthernet Long-Reach Ethernet interface Loopback Loopback interface Lspvif LSP virtual interface MFR Multilink Frame Relay bundle interface Multilink Multilink-group interface Null Null interface Tunnel Tunnel interface Vif PGM Multicast Host interface Virtual-PPP Virtual PPP interface Virtual-Template Virtual Template interface Virtual-TokenRing Virtual TokenRing bgp Border Gateway Protocol (BGP) connected Connected eigrp Enhanced Interior Gateway Routing Protocol (EIGRP) isis ISO IS-IS lisp Locator ID Separation Protocol (LISP) ospf Open Shortest Path First (OSPF) ospfv3 OSPFv3 rip Routing Information Protocol (RIP) static Static routes vmi Virtual Multipoint Interface
Have lot of fun to lab all these great OSPF features.
OSPF : Outbound filtering