https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/252896#M42390 <P>We have an existing Site-to-Site VPN tunnel between our Check Point firewall and a remote peer. Previously configured subnets are working correctly through the tunnel. However, after adding a new local subnet (e.g., 10.100.241.0/24) and a corresponding new peer subnet (e.g., 10.0.229.0/24), the new subnets are unable to communicate through the existing VPN tunnel.</P> Thu, 10 Jul 2025 03:08:05 GMT Namnh 2025-07-10T03:08:05Z https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/252896#M42390 <P>We have an existing Site-to-Site VPN tunnel between our Check Point firewall and a remote peer. Previously configured subnets are working correctly through the tunnel. However, after adding a new local subnet (e.g., 10.100.241.0/24) and a corresponding new peer subnet (e.g., 10.0.229.0/24), the new subnets are unable to communicate through the existing VPN tunnel.</P> Thu, 10 Jul 2025 03:08:05 GMT https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/252896#M42390 Namnh 2025-07-10T03:08:05Z https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/252934#M42398 <P>Did you reinstall policy after those modifications?</P> Thu, 10 Jul 2025 11:56:55 GMT https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/252934#M42398 _Val_ 2025-07-10T11:56:55Z https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/253456#M42542 <P>Hi,<BR /><BR />When adding new networks to a VPN setup, you need to add them on many locations in the policy.<BR /><BR />- Encryption Domain<BR />- Rule base<BR />- Maybe Anti-spoofing<BR /><BR />Is this all done? Has the remote peer also the updated configuration?<BR /><BR />What doe you see in the logs?<BR /><BR />Regards,<BR />Martijn</P> Fri, 18 Jul 2025 14:14:12 GMT https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/253456#M42542 Martijn 2025-07-18T14:14:12Z https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/253461#M42546 <P>Make sure to add those subnets to vpn domain and install policy, test.</P> <P>Andy</P> Fri, 18 Jul 2025 14:45:58 GMT https://community.checkpoint.com/t5/General-Topics/the-new-subnets-are-unable-to-communicate-through-the-existing/m-p/253461#M42546 the_rock 2025-07-18T14:45:58Z