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New Member

Can't ping 224.0.0.5 successfully.Why?

In my networks running ospf,there are two routers connected with two 2950G-24 switchs .The two routers can't study routing each other through ethernet port.Executing "ping 224.0.0.0",each router can receive response from all interface besides the ethernet port connected to another router.Can yoy tell me somewhere wrong?

5 REPLIES

Re: Can't ping 224.0.0.5 successfully.Why?

224.x.x.x is an IP multicast adress. This can not be used to ping a device.

Here is a part of RFC1700 that defines multicast adresses:

224.0.0.0 Base Address (Reserved) [RFC1112,JBP]

224.0.0.1 All Systems on this Subnet [RFC1112,JBP]

224.0.0.2 All Routers on this Subnet [JBP]

224.0.0.3 Unassigned [JBP]

224.0.0.4 DVMRP Routers [RFC1075,JBP]

224.0.0.5 OSPFIGP OSPFIGP All Routers [RFC1583,JXM1]

224.0.0.6 OSPFIGP OSPFIGP Designated Routers [RFC1583,JXM1]

224.0.0.7 ST Routers [RFC1190,KS14]

224.0.0.8 ST Hosts [RFC1190,KS14]

224.0.0.9 RIP2 Routers [GSM11]

224.0.0.10 IGRP Routers [Dino Farinacci]

224.0.0.11 Mobile-Agents [Bill Simpson]

224.0.0.12-224.0.0.255 Unassigned [JBP]

Regards,

Leo

Silver

Re: Can't ping 224.0.0.5 successfully.Why?

If you ping 224.0.0.5 witht he record route option you should see replies from all OSPf routers on the subnet:

ping -s 1 224.0.0.5

Pinging 224.0.0.5 with 32 bytes of data:

Reply from 224.0.0.5: bytes=32 time<10ms TTL=255

Timestamp: 10.5.80.2 : 1807993089

Reply from 224.0.0.5: bytes=32 time<10ms TTL=255

Timestamp: 10.5.80.1 : 2714159361

Reply from 224.0.0.5: bytes=32 time<10ms TTL=255

Timestamp: 10.5.80.2 : 1003211009

Reply from 224.0.0.5: bytes=32 time<10ms TTL=255

Timestamp: 10.5.80.2 : 617597185

Ping statistics for 224.0.0.5:

Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

Minimum = 0ms, Maximum = 0ms, Average = 0ms

if you do not see any replies try pinging the Unicast address. If you have IP connectivity make sure you have configured the two routers identically and that the subnet maks on the interfaces match. Other paramterts that must match are the hello timers and the dead interval timers. If these are all okay have a look at the neighbor relationship, what sate is it getting to ?

New Member

Re: Can't ping 224.0.0.5 successfully.Why?

Hi cobra,

If the network and multicast have no problem, try to use debug ip ospf events to see what's the wrong.

Hope this help

Best Regards

Teru Lei

New Member

Re: Can't ping 224.0.0.5 successfully.Why?

Using debug,i can see ospf hello packets sent to the ethernet interface,but no receiving on another router,and the neighborship between the two routers is nothing at all.In addition,on one router pinging IP address of another's ethernet interface is ok.

If i configure ip ospf network nbma,the two routers can study ospf route each other.

Whether or not the switchs between the two routers deny multicast destined 224.0.0.5???

New Member

Re: Can't ping 224.0.0.5 successfully.Why?

Hi,

Did you set some interface as passive-interface? or Did you apply access-lists block the multicast?You said "no receiving on another router" seems that there is an access-list. Or you can turn on debug on another router to compare the result, also check the config of the switch, Did you apply "storm-control multicast" or " switchport block multicast" on the switch? If you did try to turn it off. Or try not to use the 2950G switch, use a crossover cable to connect the two routers. If the problem still can not be solved, You may try to plug a sniffer to the switch and use " session monitor" command to capture the traffic between the two router to find the answer.

Hope this help

Best Regards

Teru Lei

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