ip directed-broadcast

L3IFでbroadcastを転送

R1から192.168.23.255へ通信

設定

■R1
R1#sh run int g1/0
Building configuration...

Current configuration : 93 bytes
!
interface GigabitEthernet1/0
 ip address 192.168.12.1 255.255.255.0
 negotiation auto
end

R1#
R1#sh run | s ip route
ip route 192.168.23.0 255.255.255.0 192.168.12.2


■R2
R2#sh run int g1/0
Building configuration...

Current configuration : 93 bytes
!
interface GigabitEthernet1/0
 ip address 192.168.12.2 255.255.255.0
 negotiation auto
end

R2#
R2#sh run int g2/0
Building configuration...

Current configuration : 93 bytes
!
interface GigabitEthernet2/0

#ip directed-broadcast設定の有無でどういった変化があるか検証

 ip address 192.168.23.2 255.255.255.0
 negotiation auto
end

■R3
R3#sh run int g2/0
Building configuration...

Current configuration : 93 bytes
!
interface GigabitEthernet2/0
 ip address 192.168.23.3 255.255.255.0
 negotiation auto
end

R3#
R3#
R3#sh run | s ip route
ip route 192.168.12.0 255.255.255.0 192.168.23.2

ip directed-broadcast無効

■debug ip packet有効

■R1
R1#ping 192.168.23.255 repeat 1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 192.168.23.255, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 84/84/84 ms


R1#
*Feb 16 00:04:40.403: IP: tableid=0, s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), routed via FIB
*Feb 16 00:04:40.403: IP: s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), len 100, sending
*Feb 16 00:04:40.411: IP: s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), len 100, sending full packet
*Feb 16 00:04:40.471: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:04:40.475: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, rcvd 2
*Feb 16 00:04:40.479: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, stop process pak for forus packet

■R2
*Feb 16 00:04:38.059: IP: s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:04:38.063: IP: tableid=0, s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255 (GigabitEthernet2/0), routed via RIB
*Feb 16 00:04:38.067: IP: s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255 (GigabitEthernet2/0), len 100, rcvd 5
*Feb 16 00:04:38.075: IP: tableid=0, s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), routed via FIB
*Feb 16 00:04:38.075: IP: s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), len 100, sending
*Feb 16 00:04:38.083: IP: s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), len 100, sending full packet

■R3
デバッグログ出力無し
ブロードキャストを転送しないため

■Wire shark
icmpログ出力無し

ip directed-broadcast有効

■R1
R1#ping 192.168.23.255 repeat 1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 192.168.23.255, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 96/96/96 ms
R1#
*Feb 16 00:10:22.275: IP: tableid=0, s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), routed via FIB
*Feb 16 00:10:22.275: IP: s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), len 100, sending
*Feb 16 00:10:22.283: IP: s=192.168.12.1 (local), d=192.168.23.255 (GigabitEthernet1/0), len 100, sending full packet
*Feb 16 00:10:22.359: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:10:22.363: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, rcvd 2
R1#
*Feb 16 00:10:22.367: IP: s=192.168.12.2 (GigabitEthernet1/0), d=192.168.12.1, len 100, stop process pak for forus packet
*Feb 16 00:10:22.423: IP: s=192.168.23.3 (GigabitEthernet1/0), d=192.168.12.1, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:10:22.427: IP: s=192.168.23.3 (GigabitEthernet1/0), d=192.168.12.1, len 100, rcvd 2
*Feb 16 00:10:22.431: IP: s=192.168.23.3 (GigabitEthernet1/0), d=192.168.12.1, len 100, stop process pak for forus packet

→192.168.23.3からreplyを受信


■R2
R2#
*Feb 16 00:10:18.879: IP: s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:10:18.887: IP: tableid=0, s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255 (GigabitEthernet2/0), routed via RIB
*Feb 16 00:10:18.887: IP: s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255 (GigabitEthernet2/0), g=255.255.255.255, len 100, forward directed broadcast
*Feb 16 00:10:18.895: IP: s=192.168.12.1 (GigabitEthernet1/0), d=255.255.255.255 (GigabitEthernet2/0), len 100, sending full packet
*Feb 16 00:10:18.899: IP: s=192.168.12.1 (GigabitEthernet1/0), d=192.168.23.255
R2# (GigabitEthernet2/0), len 100, rcvd 5
*Feb 16 00:10:18.907: IP: tableid=0, s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), routed via FIB
*Feb 16 00:10:18.907: IP: s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), len 100, sending
*Feb 16 00:10:18.915: IP: s=192.168.12.2 (local), d=192.168.12.1 (GigabitEthernet1/0), len 100, sending full packet

→送信先が255.255.255.255に変更される

■R3
R3#
*Feb 16 00:10:07.443: IP: s=192.168.12.1 (GigabitEthernet2/0), d=255.255.255.255, len 100, input feature, MCI Check(92), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
*Feb 16 00:10:07.447: IP: s=192.168.12.1 (GigabitEthernet2/0), d=255.255.255.255, len 100, rcvd 2
*Feb 16 00:10:07.447: IP: s=192.168.12.1 (GigabitEthernet2/0), d=255.255.255.255, len 100, stop process pak for forus packet
*Feb 16 00:10:07.451: IP: tableid=0, s=192.168.23.3 (local), d=192.168.12.1 (GigabitEthernet2/0), routed via FIB
*Feb 16 00:10:07.455: IP: s=192.168.23.3 (local), d=192.168.12.1 (GigabitEthernet2/0), len 100, sending
R3#
*Feb 16 00:10:07.463: IP: s=192.168.23.3 (local), d=192.168.12.1 (GigabitEthernet2/0), len 100, sending full packet

→192.168.12.1から255.255.255.255宛へのrequestに、192.168.23.3からreply
ユニキャストでのping