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Date:      Mon, 19 Mar 2012 09:04:43 +0100
From:      Palle Girgensohn <girgen@FreeBSD.org>
To:        freebsd-jail@freebsd.org
Subject:   Re: VMNET - problem with epair in jail, cannot ping itself?
Message-ID:  <4F66E89B.9090704@FreeBSD.org>
In-Reply-To: <4F66E535.9010607@gmx.com>
References:  <4F6673FD.2040809@FreeBSD.org> <4F66E535.9010607@gmx.com>

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Nikos Vassiliadis skrev:
> On 3/19/2012 12:47 AM, Palle Girgensohn wrote:
>> Hi!
>>
>> When I create an epair and pu one end inside a jail, and give that
>> interface an IP address, the jail still seems to want to use the lo0
>> interface to route traffic to that interface on the inside.
>>
>> Everything else works, I can set up bridges just like it would be an
>> ethernet switch, add services on the inside, it is all fine, except this
>> little annoying bug(?).
>>
>> See here:
>>
>> [root@hostname /home/girgen]# ifconfig epair create
>> epair0a
>> [root@hostname /home/girgen]# jail -c vnet name=bar host.hostname=bar
>> path=/ persist
>> [root@hostname /home/girgen]# jls
>>     JID  IP Address      Hostname                      Path
>>       1  -               bar                           /
>> [root@hostname /home/girgen]# ifconfig epair0b vnet bar
>> [root@hostname /home/girgen]# ifconfig -a
>> bce0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST>  metric 0 mtu
>> 1500
>>     options=c01bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO,LINKSTATE>
>>
>>     ether 00:23:7d:23:9d:44
>>     inet 1.2.3.144 netmask 0xffffffc0 broadcast 1.2.3.191
>>     inet6 fe80::223:7dff:fe23:9d44%bce0 prefixlen 64 scopeid 0x1
>>     nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>     media: Ethernet autoselect (1000baseT<full-duplex>)
>>     status: active
>> bce1: flags=8802<BROADCAST,SIMPLEX,MULTICAST>  metric 0 mtu 1500
>>     options=c01bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO,LINKSTATE>
>>
>>     ether 00:23:7d:23:9d:42
>>     nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>     media: Ethernet autoselect
>> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST>  metric 0 mtu 16384
>>     options=3<RXCSUM,TXCSUM>
>>     inet6 ::1 prefixlen 128
>>     inet6 fe80::1%lo0 prefixlen 64 scopeid 0x9
>>     inet 127.0.0.1 netmask 0xff000000
>>     nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
>> epair0a: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST>  metric 0 mtu
>> 1500
>>     options=8<VLAN_MTU>
>>     ether 02:f9:05:00:0a:0a
>>     nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
>>     media: Ethernet 10Gbase-T (10Gbase-T<full-duplex>)
>>     status: active
>> [root@hostname /home/girgen]# jexec bar ifconfig -a
>> lo0: flags=8008<LOOPBACK,MULTICAST>  metric 0 mtu 16384
>>     options=3<RXCSUM,TXCSUM>
>>     nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
>> epair0b: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST>  metric 0 mtu
>> 1500
>>     options=8<VLAN_MTU>
>>     ether 02:f9:05:00:0b:0b
>>     nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
>>     media: Ethernet 10Gbase-T (10Gbase-T<full-duplex>)
>>     status: active
>> [root@hostname /home/girgen]# jexec bar ifconfig epair0b 10.1.1.2
>> netmask 0xffffff00 up
>> [root@hostname /home/girgen]# jexec bar ping 10.1.1.2
>> PING 10.1.1.2 (10.1.1.2): 56 data bytes
>> ^C
>> --- 10.1.1.2 ping statistics ---
>> 3 packets transmitted, 0 packets received, 100.0% packet loss
>> [root@hostname /home/girgen]# jexec bar route -n get  10.1.1.2
>>     route to: 10.1.1.2
>> destination: 10.1.1.2
>>    interface: lo0
>>        flags:<UP,HOST,DONE,STATIC>
>>   recvpipe  sendpipe  ssthresh  rtt,msec    mtu        weight    expire
>>         0         0         0         0     16384         1         0
>> [root@hostname /home/girgen]#
>>
>>
>>
>> Now why would the jail think that lo0 is the way to go to find 10.1.1.2?
> 
> That's because 10.1.1.2 is a local address for jail bar and all local
> addresses are reachable via lo0. Keep in mind that this is the vnet's
> lo0 and has nothing to do with the host's lo0. Just "up" your vnet's lo0
> interface and everything will be ok. The lo0 loopback interface is
> prerequisite for networking.
> 
> HTH, Nikos

Ah, OK, thanks. I had not grasped that.

But it does not work?

[root@hostname /home/girgen]# jexec bar ifconfig lo0 localhost up
[root@hostname /home/girgen]# jexec bar ifconfig -a
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 16384
	options=3<RXCSUM,TXCSUM>
	inet6 ::1 prefixlen 128
	inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
	inet 127.0.0.1 netmask 0xff000000
	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
epair0b: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
1500
	options=8<VLAN_MTU>
	ether 02:f9:05:00:0b:0b
	inet6 fe80::f9:5ff:fe00:b0b%epair0b prefixlen 64 scopeid 0x2
	inet 10.1.1.2 netmask 0xffffff00 broadcast 10.1.1.255
	nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
	media: Ethernet 10Gbase-T (10Gbase-T <full-duplex>)
	status: active
[root@hostname /home/girgen]# jexec bar ping 10.1.1.2
PING 10.1.1.2 (10.1.1.2): 56 data bytes
^C
--- 10.1.1.2 ping statistics ---
3 packets transmitted, 0 packets received, 100.0% packet loss
[root@hostname /home/girgen]# jexec bar ping localhost
PING localhost (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.045 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.030 ms
^C
--- localhost ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.030/0.037/0.045/0.007 ms
[root@hostname /home/girgen]#



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