[ds6] Help required: Unable to Ping Global Ipv6 address from different host

Peter Bieringer pb at bieringer.de
Wed Apr 5 12:39:29 CEST 2006
Previous message: [ds6] Help required: Unable to Ping Global Ipv6 address from different host
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somashekar schrieb:

> I have two desktops which are installed with Fedora Core release 3,
> connected with each other using Ethernet hub (crash net)
> 
> They are not connected to the main network (i.e., uplink is not connected)
> 
> I am trying to establishing a network where the two PCs can communicate
> each other using IPv6 addresses.
> 
> Both hosts are IPv6 enabled.
> 
>  
> 
> Iam able to ping the link-local ipv6 address from one host to another host.
> 
> But unable to ping the global ipv6 address.
> 
>  
> 
> The configuration of the two PCs, which are named as Host-A and Host-B
> are as shown below.
> 
>  
> 
> Host-A configuration
> 
> -----------------------------
> 
> After reboot, [root at localhost ~]# ifconfig
> 
> lo        Link encap:Local Loopback
> 
>           inet addr:127.0.0.1  Mask:255.0.0.0
> 
>           inet6 addr: ::1/128 Scope:Host
> 
>           UP LOOPBACK RUNNING  MTU:16436  Metric:1
> 
>           RX packets:3586 errors:0 dropped:0 overruns:0 frame:0
> 
>           TX packets:3586 errors:0 dropped:0 overruns:0 carrier:0
> 
>           collisions:0 txqueuelen:0
> 
>           RX bytes:4476276 (4.2 Mb)  TX bytes:4476276 (4.2 Mb)
> 
> -----------------------------------------------------------------------------------------------------
> 
> Iam assigning 10.255.114.96 address to Host-A
> 
>  
> 
> [root at localhost ~]#  ifconfig eth0 10.255.114.96
> 
>  
> 
> eth0      Link encap:Ethernet  HWaddr 00:08:74:2E:41:54
> 
>           inet addr:10.255.114.96  Bcast:10.255.255.255  Mask:255.0.0.0
> 
>           inet6 addr: fe80::208:74ff:fe2e:4154/64 Scope:Link
> 
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> 
>           RX packets:1 errors:0 dropped:0 overruns:0 frame:0
> 
>           TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
> 
>           collisions:0 txqueuelen:1000
> 
>           RX bytes:64 (64.0 b)  TX bytes:3910 (3.8 Kb)
> 
>           Base address:0xecc0 Memory:ff8e0000-ff900000

No IPv6 address with global scope assigned!

> -----------------------------------------------------------------------------------------------
> 
> Initial /etc/resolv.conf
> 
>  
> 
> ; generated by /sbin/dhclient-script
> 
> search xerox.celstream.com
> 
> nameserver 10.255.114.25
> 
>  
> 
> ---------------------------------------------------------------------
> 
> I have used bind-9.3.2 for DNS Server configuration.
> 
>  
> 
> After changing resolv.conf as shown below
> 
>  
> 
> ; generated by /sbin/dhclient-script
> 
> search celstream1.com
> 
> nameserver 10.255.114.96
> 
>  
> 
> -------------------------------------------------------------------------
> 
> Ping DNS Server “celstream1.com”
> 
>  
> 
> [root at localhost ~]# ping ns1.celstream1.com
> 
>  
> 
> PING ns1.celstream1.com (10.255.114.96) 56(84) bytes of data.
> 
> 64 bytes from ns1.celstream1.com (10.255.114.96): icmp_seq=0 ttl=64
> time=0.056 ms
> 
> 64 bytes from ns1.celstream1.com (10.255.114.96): icmp_seq=1 ttl=64
> time=0.072 ms
> 
> 64 bytes from ns1.celstream1.com (10.255.114.96): icmp_seq=2 ttl=64
> time=0.068 ms
> 
> 64 bytes from ns1.celstream1.com (10.255.114.96): icmp_seq=3 ttl=64
> time=0.068 ms
> 
>  
> 
> --- ns1.celstream1.com ping statistics ---
> 
> 4 packets transmitted, 4 received, 0% packet loss, time 3000ms
> 
> rtt min/avg/max/mdev = 0.056/0.066/0.072/0.006 ms, pipe 2
> 
> ------------------------------------------------------------------------------------------------------------------------------
> 
>  
> 
> Ping6 Link-local ipv6 address fe80::208:74ff:fe2e:4154
> 
>  
> 
> [root at localhost ~]# ping6 -I eth0 fe80::208:74ff:fe2e:4154
> 
>  
> 
> PING fe80::208:74ff:fe2e:4154(fe80::208:74ff:fe2e:4154) from ::1 eth0:
> 56 data bytes
> 
> 64 bytes from fe80::208:74ff:fe2e:4154: icmp_seq=0 ttl=64 time=0.111 ms
> 
> 64 bytes from fe80::208:74ff:fe2e:4154: icmp_seq=1 ttl=64 time=0.060 ms
> 
> 64 bytes from fe80::208:74ff:fe2e:4154: icmp_seq=2 ttl=64 time=0.060 ms
> 
> 64 bytes from fe80::208:74ff:fe2e:4154: icmp_seq=3 ttl=64 time=0.059 ms
> 
>  
> 
> --- fe80::208:74ff:fe2e:4154 ping statistics ---
> 
> 4 packets transmitted, 4 received, 0% packet loss, time 2999ms
> 
> rtt min/avg/max/mdev = 0.059/0.072/0.111/0.023 ms, pipe 2
> 
>  
> 
> -----------------------------------------------------------------------------------------------------------------------------
> 
> /etc/sysconfig/network-scripts/ifcfg-eth0
> 
>  
> 
> DEVICE=eth0
> 
> BOOTPROTO=dhcp
> 
> ONBOOT=yes
> 
> TYPE=Ethernet
> 
> IPV6INIT=yes
> 
> IPV6TO4INIT=yes

Why is this set?

> DHCP6C=yes

Hui, never seen this option.

> IPV6ADDR=fe80::208:74ff:fe2e:4154

That's not necessary, you do not need to specify link local address here.

> -----------------------------------------------------------------------------
> 
> [root at localhost ~]# ip -6 route show
> 
>  
> 
> unreachable ::/96 dev lo  metric 1024  error -101 mtu 16436 advmss 16376
> metric10 64
> 
> unreachable ::ffff:0.0.0.0/96 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:a00::/24 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:7f00::/24 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:a9fe::/32 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:ac10::/28 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:c0a8::/32 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 2002:e000::/19 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> unreachable 3ffe:ffff::/32 dev lo  metric 1024  error -101 mtu 16436
> advmss 16376 metric10 64
> 
> fe80::/64 dev eth0  metric 256  mtu 1500 advmss 1440 metric10 64
> 
> ff00::/8 dev eth0  metric 256  mtu 1500 advmss 1440 metric10 1
> 
> unreachable default dev lo  proto none  metric -1  error -101 metric10 255
> 
>  
> 
> -----------------------------------------------------------------------------
> 
> [root at localhost ~]# ip route show
> 
>  
> 
> [root at localhost network-scripts]# ip route show
> 
> 169.254.0.0/16 dev lo  scope link
> 
> 10.0.0.0/8 dev eth0  proto kernel  scope link  src 10.255.114.96
> 
> ------------------------------------------------------------------------------
> 
> ping6 Host-B Ipv6 address
> 
>  
> 
> [root at localhost network-scripts]# ping6 -I eth0 fe80::206:5bff:fe20:406c
> 
>  
> 
> PING fe80::206:5bff:fe20:406c(fe80::206:5bff:fe20:406c) from
> fe80::208:74ff:fe2e:4154 eth0: 56 data bytes
> 
> 64 bytes from fe80::206:5bff:fe20:406c: icmp_seq=0 ttl=64 time=1.31 ms
> 
> 64 bytes from fe80::206:5bff:fe20:406c: icmp_seq=1 ttl=64 time=0.500 ms
> 
> 64 bytes from fe80::206:5bff:fe20:406c: icmp_seq=2 ttl=64 time=0.435 ms
> 
>  
> 
> --- fe80::206:5bff:fe20:406c ping statistics ---
> 
> 3 packets transmitted, 3 received, 0% packet loss, time 2000ms
> 
> rtt min/avg/max/mdev = 0.435/0.750/1.316/0.401 ms, pipe 2
> 
> ------------------------------------------------------------------------------
> 
> Using dibbler-0.4.1-linux.tar for DHCP Ipv6 server and client
> 
> I got the Global inet6 addr which is 2000::bd
> 
>  
> 
> [root at localhost ~]# ifconfig
> 
> eth0      Link encap:Ethernet  HWaddr 00:08:74:2E:41:54
> 
>           inet addr:10.255.114.96  Bcast:10.255.255.255  Mask:255.0.0.0
> 
>           inet6 addr: fe80::208:74ff:fe2e:4154/64 Scope:Link
> 
>           inet6 addr: 2000::bd/128 Scope:Global

Totally bad, /128 is not allowed here, must be at least /64

> ------------------------------------------------------------------------------
> 
> ping6 Host-B Global Ipv6 addr 2000::7f from Host-A
> 
>  
> 
> [root at localhost ~]# ping6 -I eth0 2000::7f
> 
> connect: Network is unreachable
> 

> -------------------------------------------------------------------------
> 
> After running dibbler-client
> 
>  
> 
> [root at localhost ~]# ifconfig
> 
> eth0      Link encap:Ethernet  HWaddr 00:06:5B:20:40:6C
> 
>           inet addr:10.255.114.176  Bcast:10.255.255.255  Mask:255.0.0.0
> 
>           inet6 addr: fe80::206:5bff:fe20:406c/64 Scope:Link
> 
>           inet6 addr: 2000::7f/128 Scope:Global

/128 is bad!


> The problem is
> 
>  
> 
> I am able to ping6 the link-local ipv6 addresses across the two hosts.
> And also able to ping6 the DHCP assigned global ipv6 address within the
> same host but not from the other host. It says “Network is unreachable”
> as shown below.

For sure, because assigning a /128 on NIC. Try

1) /64
2) Do not use 2000:: as prefix without proper TLA and SLAs, use e.g.
fec0:: or fd00:: for tests.

	Peter
-- 
Dr. Peter Bieringer                     http://www.bieringer.de/pb/
GPG/PGP Key 0x958F422D                       mailto:pb at bieringer.de
Deep Space 6 Co-Founder and Core Member  http://www.deepspace6.net/
Previous message: [ds6] Help required: Unable to Ping Global Ipv6 address from different host
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