Jail with public IP alias

[Patrick]

On Thu, Aug 29, 2013 at 12:07 PM, Alejandro Imass <aimass at yabarana.com> wrote:
> On Thu, Aug 29, 2013 at 5:03 AM, Frank Leonhardt <frank2 at fjl.co.uk> wrote:
>> On 29/08/2013 09:52, Frank Leonhardt wrote:
>>>
>
> Hi Frank thanks for taking the time to try to replicate this. Here is
> all the detailed info
>
> 8.1-RELEASE
>
> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>         options=209b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC>
>         ether 00:31:88:bd:b9:3a
>         inet xxx.yyy.52.74 netmask 0xffffff80 broadcast xxx.yyy.52.127
>         inet xxx.yyy.52.70 netmask 0xffffff80 broadcast xxx.yyy.52.127
>         inet xxx.yyy.52.71 netmask 0xffffff80 broadcast xxx.yyy.52.127
>         inet xxx.yyy.52.73 netmask 0xffffff80 broadcast xxx.yyy.52.127
>         media: Ethernet autoselect (1000baseT <full-duplex>)
>         status: active
>
> I use rc.conf standard practice for aliases:
>
> ifconfig_em0="inet xxx.yyy.52.74 netmask 255.255.255.128 -tso"
> ifconfig_em0_alias0="inet xxx.yyy.52.70  netmask 255.255.255.128 -tso"
> ifconfig_em0_alias1="inet xxx.yyy.52.71  netmask 255.255.255.128 -tso"
> ifconfig_em0_alias2="inet xxx.yyy.52.73  netmask 255.255.255.128 -tso"
>
> nune# netstat -rn
> Routing tables
>
> Internet:
> Destination        Gateway            Flags    Refs      Use  Netif Expire
> default            xxx.yyy.52.1       UGS       168 182183463    em0
> 127.0.0.1          link#4             UH          0        0    lo0
> [... internal aliases to lo0 here...]
> xxx.yyy.52.0/25    link#1             U           0    68581    em0
> xxx.yyy.52.70      link#1             UHS         0    14363    lo0
> xxx.yyy.52.71      link#1             UHS         0    64765    lo0
> xxx.yyy.52.73      link#1             UHS         0        0    lo0
> xxx.yyy.52.74      link#1             UHS         0    29170    lo0
>
> Note the Netif Expire on 71,73,74 are showing lo0 could this be the problem?
>
> nune# ssh -b xxx.yyy.52.71 foo at bar
> Password:
>
>> w -n
>  3:15PM  up 130 days, 22:30, 3 users, load averages: 0.00, 0.02, 0.00
> USER             TTY      FROM              LOGIN@  IDLE WHAT
> [...]
> foo           pts/24   xxx.yyy.52.74     3:14PM     - w -n
>
> I don't know why mine is showing 74 and from your example it should be
> showing 71. Did you see the article below?
>
> http://serverfault.com/questions/12285/when-ip-aliasing-how-does-the-os-determine-which-ip-address-will-be-used-as-sour
>
> This seems to be a pretty common issue or it's just a
> miss-configuration problem?
>
> Thanks!
>
> Alejandro Imass
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Aliases should have a netmask of 255.255.255.255. What you seeing is
not typical behaviour on FreeBSD.

http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/configtuning-virtual-hosts.html

Patrick