Reverse path filter parameter "rp_filter" in 12c RAC installation

Warning : Reverse path filter parameter "rp_filter"
in 12c RAC installation

Oracle Support ID :  (Doc ID 1286796.1)

Symptoms :

Case 1 :

During Grid Infrastructure Installation, you will get warning and doesn't fix after running  /tmp/CVU_12.1.0.2.0_oracle/runfixup.sh on both node.

Case 2 :

Interconnect packets may potentially be blocked/discarded.  CAN'T START MORE THAN ONE INST DUE TO IMR RECONF HUNG. The rp_filter parameter can be set globally on all NICs, or specific on each NIC. The maximum (between the "all" and the specific interface) value is taken.

The values are defined as follows: 
rp_filter - INTEGER

•          0 - No source validation.
• ·      1 - Strict mode as defined in RFC3704 Strict Reverse Path Each incoming packet is tested against the FIB and if the interface is not the best reverse path the packet check will fail. By default failed packets are discarded.
• ·      2 - Loose mode as defined in RFC3704 Loose Reverse Path Each incoming packet's source address is also tested against the FIB and if the source address is not reachable via any interface the packet check will fail.

net.ipv4.conf.eth1.rp_filter = 2
net.ipv4.conf.eth2.rp_filter = 2

Private Interconnect :

NODE 1

eth1     10.10.10.122

eth2     20.20.20.122

NODE 2

eth1     10.10.10.123

eth2     20.20.20.123

[root@rac122 ~]# vi /etc/sysctl.conf

net.ipv4.conf.eth1.rp_filter = 2

net.ipv4.conf.eth2.rp_filter = 2

[root@rac122 ~]# sysctl -p

net.ipv4.ip_forward = 0

net.ipv4.conf.default.rp_filter = 1

net.ipv4.conf.default.accept_source_route = 0

kernel.sysrq = 0

kernel.core_uses_pid = 1

net.ipv4.tcp_syncookies = 1

kernel.msgmnb = 65536

kernel.msgmax = 65536

fs.file-max = 6815744

kernel.sem = 250 32000 100 128

kernel.shmmni = 4096

kernel.shmall = 1073741824

kernel.shmmax = 4398046511104

net.core.rmem_default = 262144

net.core.rmem_max = 4194304

net.core.wmem_default = 262144

net.core.wmem_max = 1048576

fs.aio-max-nr = 1048576

net.ipv4.ip_local_port_range = 9000 65500

kernel.panic_on_oops = 1

net.ipv4.conf.eth1.rp_filter = 2

net.ipv4.conf.eth2.rp_filter = 2

[root@rac123 ~]# vi /etc/sysctl.conf

net.ipv4.conf.eth1.rp_filter = 2

net.ipv4.conf.eth2.rp_filter = 2

[root@rac122 ~]# sysctl -p

net.ipv4.ip_forward = 0

net.ipv4.conf.default.rp_filter = 1

net.ipv4.conf.default.accept_source_route = 0

kernel.sysrq = 0

kernel.core_uses_pid = 1

net.ipv4.tcp_syncookies = 1

kernel.msgmnb = 65536

kernel.msgmax = 65536

fs.file-max = 6815744

kernel.sem = 250 32000 100 128

kernel.shmmni = 4096

kernel.shmall = 1073741824

kernel.shmmax = 4398046511104

net.core.rmem_default = 262144

net.core.rmem_max = 4194304

net.core.wmem_default = 262144

net.core.wmem_max = 1048576

fs.aio-max-nr = 1048576

net.ipv4.ip_local_port_range = 9000 65500

kernel.panic_on_oops = 1

net.ipv4.conf.eth1.rp_filter = 2

net.ipv4.conf.eth2.rp_filter = 2

Click on check again on installation to verify .....