# OSPF Packets and Neighbor Discovery **URL:** \ **Category:** Lessons Discussion\ **Created:** [December 22, 2016, 1:00am UTC](https://forum.networklessons.com/t/ospf-packets-and-neighbor-discovery/916 "2016-12-22T01:00:06Z")\ **Posts on this page:** 1\ **Showing post:** 100
**Author:** ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)\ **Post date:** [October 14, 2021, 4:54am UTC](https://forum.networklessons.com/t/ospf-packets-and-neighbor-discovery/916/100 "2021-10-14T04:54:02Z")
Hello Alessandro You’ve configured the interfaces correctly, [using a /31 subnet mask](https://forum.networklessons.com/t/classless-interdomain-routing-cidr/1218/11). However, when you configured OSPF, you didn’t advertise that network. You must use the `network` command under the OSPF configuration to indicate which subnets will participate in OSPF and thus which interfaces will begin sending OSPF hello packets to establish adjacencies. In your case, you must add the `network 192.168.1.2 0.0.0.1 area 0` command under the OSPF configuration mode for both routers. Take a look at this lesson for more details: > **[Basic OSPF Configuration](https://networklessons.com/ospf/basic-ospf-configuration)** > > This lesson explains the basics of an OSPF configuration on Cisco IOS. We look at different configuration and show commands. I hope this has been helpful! Laz --- _[View the full topic](https://forum.networklessons.com/t/ospf-packets-and-neighbor-discovery/916)._