Jail with public IP alias

Alejandro Imass aimass at yabarana.com
Thu Aug 29 19:07:46 UTC 2013

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


em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        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 -tso"
ifconfig_em0_alias0="inet xxx.yyy.52.70  netmask -tso"
ifconfig_em0_alias1="inet xxx.yyy.52.71  netmask -tso"
ifconfig_em0_alias2="inet xxx.yyy.52.73  netmask -tso"

nune# netstat -rn
Routing tables

Destination        Gateway            Flags    Refs      Use  Netif Expire
default            xxx.yyy.52.1       UGS       168 182183463    em0          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

> 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?


This seems to be a pretty common issue or it's just a
miss-configuration problem?


Alejandro Imass

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