From: Petr Lapukhov (petrsoft@gmail.com)
Date: Sat Apr 01 2006 - 10:24:02 GMT-3
Henk,
Looking on DocCD
http://www.cisco.com/univercd/cc/td/doc/product/software/ios124/124cr/himc_r/
mlt_i1h.htm#wp1075964
....
If you need to send a directed broadcast to the subnet, the outgoing
interface of the last hop
router can be configured with an IP broadcast address of x.x.x.255, where
x.x.x.0 is the
subnet that you are trying to reach; otherwise the packet will be converted
to
255.255.255.255.
...
HTH
Petr
2006/3/27, Henk de Tombe <henk.de.tombe@qi.nl>:
>
> That's what I've seen in the output of the debug:
>
>
>
> The IOS version I've used is:
>
>
>
> IOS (tm) 3700 Software (C3745-JK9O3S-M), Version 12.2(15)T14, RELEASE
> SOFTWARE (fc4)
>
>
>
> Regards,
>
> Henk
>
>
>
> *Van:* Petr Lapukhov [mailto:petrsoft@gmail.com]
> *Verzonden:* maandag 27 maart 2006 15:07
> *Aan:* Henk de Tombe
> *CC:* CCIE LAB
> *Onderwerp:* Re: multicast helper-map configuration review
>
>
>
> Do I get you right:
>
> You point on fact, that even if we specify broadcast address
> in "ip multicast-helper map", IOS still uses interface default?
>
> and if we need to change that behavior, we should change
> broadcast address on interfacse?
>
> Petr
>
> 2006/3/27, Henk de Tombe <henk.de.tombe@qi.nl>:
>
> Hi Group,
>
>
>
> I want to ask you something, I've configured the Multicast helper-map.
> Configs are posted below:
>
>
>
> ROUTER01#sh run
>
> Building configuration...
>
>
>
> Current configuration : 2041 bytes
>
> !
>
> version 12.2
>
> service timestamps debug datetime msec
>
> service timestamps log datetime msec
>
> no service password-encryption
>
> !
>
> hostname ROUTER01
>
> !
>
> logging queue-limit 100
>
> !
>
> memory-size iomem 10
>
> ip subnet-zero
>
> !
>
> !
>
> ip multicast-routing
>
> ip audit notify log
>
> ip audit po max-events 100
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> no voice hpi capture buffer
>
> no voice hpi capture destination
>
> !
>
> !
>
> mta receive maximum-recipients 0
>
> !
>
> !
>
> !
>
> !
>
> interface FastEthernet0/0
>
> ip address 192.168.11.1 255.255.255.0
>
> ip pim dense-mode
>
> ip multicast helper-map broadcast 224.11.11.11 100
>
> duplex auto
>
> speed auto
>
> !
>
> interface Serial0/0
>
> ip address 164.1.0.1 255.255.255.0
>
> ip pim dense-mode
>
> encapsulation frame-relay
>
> ip ospf hello-interval 2
>
> ip ospf dead-interval 4
>
> frame-relay map ip 164.1.0.3 103 broadcast
>
> frame-relay map ip 164.1.0.5 105 broadcast
>
> no frame-relay inverse-arp
>
> frame-relay lmi-type cisco
>
> !
>
> interface FastEthernet0/1
>
> no ip address
>
> shutdown
>
> duplex auto
>
> speed auto
>
> !
>
> interface Serial0/1
>
> no ip address
>
> shutdown
>
> !
>
> router ospf 1
>
> log-adjacency-changes
>
> network 164.1.0.1 0.0.0.0 area 0
>
> network 192.168.11.1 0.0.0.0 area 1
>
> neighbor 164.1.0.3 priority 1
>
> !
>
> ip http server
>
> no ip http secure-server
>
> ip classless
>
> !
>
> !
>
> !
>
> access-list 100 permit udp any any eq domain
>
> access-list 100 deny udp any any
>
> !
>
> call rsvp-sync
>
> !
>
> !
>
> mgcp profile default
>
> !
>
> dial-peer cor custom
>
>
>
>
>
> ROUTER03(config-if)#do sh run
>
> Building configuration...
>
>
>
> Current configuration : 2174 bytes
>
> !
>
> version 12.2
>
> service timestamps debug datetime msec
>
> service timestamps log datetime msec
>
> no service password-encryption
>
> !
>
> hostname ROUTER03
>
> !
>
> logging queue-limit 100
>
> !
>
> ip subnet-zero
>
> !
>
> !
>
> no ip domain lookup
>
> !
>
> ip multicast-routing
>
> ip audit notify log
>
> ip audit po max-events 100
>
> mpls ldp logging neighbor-changes
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> !
>
> no voice hpi capture buffer
>
> no voice hpi capture destination
>
> !
>
> !
>
> mta receive maximum-recipients 0
>
> !
>
> !
>
> !
>
> !
>
> interface FastEthernet0/0
>
> ip address 192.168.33.3 255.255.255.0
>
> ip broadcast-address 192.168.33.255
>
> ip directed-broadcast
>
> duplex auto
>
> speed auto
>
> !
>
> interface FastEthernet0/1
>
> no ip address
>
> shutdown
>
> duplex auto
>
> speed auto
>
> !
>
> interface Serial1/0
>
> ip address 164.1.0.3 255.255.255.0
>
> ip pim dense-mode
>
> ip multicast helper-map 224.11.11.11 192.168.33.255 100
>
> encapsulation frame-relay
>
> ip ospf hello-interval 2
>
> ip ospf dead-interval 4
>
> no ip mroute-cache
>
> serial restart_delay 0
>
> frame-relay map ip 164.1.0.1 301 broadcast
>
> no frame-relay inverse-arp
>
> frame-relay lmi-type cisco
>
> !
>
> interface Serial1/1
>
> no ip address
>
> shutdown
>
> serial restart_delay 0
>
> !
>
> interface Serial1/2
>
> no ip address
>
> shutdown
>
> serial restart_delay 0
>
> !
>
> interface Serial1/3
>
> no ip address
>
> shutdown
>
> serial restart_delay 0
>
> !
>
> router ospf 1
>
> log-adjacency-changes
>
> network 164.1.0.3 0.0.0.0 area 0
>
> network 192.168.33.3 0.0.0.0 area 3
>
> !
>
> ip http server
>
> no ip http secure-server
>
> ip classless
>
> !
>
> !
>
> !
>
> access-list 100 permit udp any any eq domain
>
> access-list 100 deny udp any any
>
>
>
>
>
>
>
>
>
> Please mind that I have no "ip forward protocol udp 53" statement in the
> configuration because this is default configuration.
>
>
>
>
>
> I've tested the above configuration with the following setup:
>
>
>
> switch#host
>
> Translating "host"...domain server (255.255.255.255)
>
> % Unknown command or computer name, or unable to find computer address
>
> switch#sh log | i Vlan
>
> 1d01h: IP: s=192.168.11.8 (local), d=255.255.255.255 (Vlan1), len 50,
> sending broad/multicast
>
> 1d01h: IP: s= 192.168.11.8 (local), d=255.255.255.255 (Vlan1), len 50,
> sending full packet
>
> 1d01h: IP: s=192.168.33.8 (local), d= 255.255.255.255 (Vlan3), len 50,
> sending broad/multicast
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 50,
> sending full packet
>
> 1d01h: IP: s=192.168.11.8 (Vlan3), d=255.255.255.255, len 50, unroutable
>
>
>
> The switch is attached with VLAN1 to ROUTER1 and with VLAN3 to ROUTER3.
> The
> switch tries to translate "host" and sends a broadcast on all VLANS.
>
>
>
> 1d01h: IP: s=192.168.11.8 (local), d=255.255.255.255 (Vlan1), len 50,
> sending broad/multicast
>
> 1d01h: IP: s=192.168.11.8 (local), d=255.255.255.255 (Vlan1), len 50,
> sending full packet
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 50,
> sending broad/multicast
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 50,
> sending full packet
>
>
>
> After a split second the following entry appears in the debug information:
>
> 1d01h: IP: s= 192.168.11.8 (Vlan3), d=255.255.255.255, len 50, unroutable
>
>
>
> IP packets of VLAN1 are "wandering" on VLAN3, this means that ROUTER3 has
> forwarded the broadcast address. To make this absolutely sure, I've
> performed another test:
>
>
>
> Switch# debug ip packet det dump
>
> Switch#GROUPSTUDY <----------------------------
>
> switch#SH LOG | b Vlan3
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 56,
> sending broad/multicast
>
> 1d01h: UDP src=54593, dst=53
>
> 074042D0: 45000038 00000000 E..8....
>
> 074042E0: FF11DA04 C0A82108 FFFFFFFF D5410035 ..Z.@(!.....UA.5
>
> 074042F0: 00240000 005E0100 00010000 00000000 .$...^..........
>
> 07404300: 0A47524F 55505354 55445900 00010001 .GROUPSTUDY.....
> <--------------------------------------------------------------
>
> 07404310:
>
>
>
> I was looking in the log file and saw that the destination ip address is
> 255.255.255.255 . I the configuration of ROUTER3 I've configured the
> helper-map to send traffic to address 192.168.33.255, ip multicast
> helper-map 224.11.11.11 192.168.33.255 100.
>
>
>
> I have to change the ip broadcast-address of the egress interface on
> ROUTER3,
>
>
>
> ROUTER03#show ip int fa0/0
>
> FastEthernet0/0 is up, line protocol is up
>
> Internet address is 192.168.33.3/24
>
> Broadcast address is 255.255.255.255
>
>
>
> ROUTER03#conf
>
> *Mar 1 04:31:28.106 : %SYS-5-CONFIG_I: Configured from console by console
> t
>
> Enter configuration commands, one per line. End with CNTL/Z.
>
> ROUTER03(config)#int fa0/0
>
> ROUTER03(config-if)#ip broad
>
> ROUTER03(config-if)#ip broadcast-address 192.168.33.255
>
> ROUTER03(config-if)#
>
> ROUTER03(config-if)#do sh ip int fa0/0
>
> FastEthernet0/0 is up, line protocol is up
>
> Internet address is 192.168.33.3/24
>
> Broadcast address is 192.168.33.255
>
>
>
>
>
> switch#clear log
>
> Clear logging buffer [confirm]
>
> switch#end
>
> Translating "end"...domain server ( 255.255.255.255)
>
> % Unknown command or computer name, or unable to find computer address
>
> switch#sh log | i Vlan3
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 49,
> sending broad/multicast
>
> 1d01h: IP: s=192.168.33.8 (local), d= 255.255.255.255 (Vlan3), len 49,
> sending full packet
>
> 1d01h: IP: s=192.168.11.8 (Vlan3), d=192.168.33.255 (Vlan3), len 49, rcvd
> local pkt
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 49,
> sending broad/multicast
>
> 1d01h: IP: s= 192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 49,
> sending full packet
>
> 1d01h: IP: s=192.168.11.8 (Vlan3), d= 192.168.33.255 (Vlan3), len 49, rcvd
> local pkt
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 49,
> sending broad/multicast
>
> 1d01h: IP: s=192.168.33.8 (local), d=255.255.255.255 (Vlan3), len 49,
> sending full packet
>
> 1d01h: IP: s= 192.168.11.8 (Vlan3), d=192.168.33.255 (Vlan3), len 49, rcvd
> local pkt
>
>
>
> The switch now receives broadcasts send to 192.168.33.255 .
>
> The ip broadcast-address of the Ethernet interface overrules the
> helper-map
> statement, so if you are asked to send packets to x.x.x.255 you have to
> change the interface broadcast address.
>
> The Doc CD doesn't help us much out,
>
>
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr
> _c/ipcpt3/1cfmulti.htm#wp1003511
>
<http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fip
> r_c/ipcpt3/1cfmulti.htm#wp1003511>
>
> For the ones who have IEWB version 2.0, LAB 8 task 7.8 - 7.9 doesn't have
> the ip broadcast address entry as well.
>
>
>
> If I'm totally wrong on this one please let me know,
>
>
>
>
>
> Regards,
>
> Henk
>
> _______________________________________________________________________
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