A question about ssh RSA key connection

[徐广]

Hi
I recently met with a problem when trying to set up ssh connection
through the ssh key

I first create a key through command ssh-keygen -t rsa -f
/.ssh/pmcftp_id_rsa -P "" , two files would be created under /.ssh
pmcftp_id_rsa and pmcftp_id_rsa.pub, then I insert an entry into the
.pub file - from="47.154.169.129,47.154.169.128"  this should
restrickt that the ssh key should only work for sources of these two
ips.
Then I push the public key to another server under ~pmcftp/.ssh, after
that, I start the ssh connection through command ssh -I pmcftp -i.
./ssh/pmcftp_id_rsa <server ip>, the ssh connection would be set up
without asking for the passwd.
But, when I create the ssh key on a server that has several ip
address, like following:
=====
ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu
8232 index 1
        inet 127.0.0.1 netmask ff000000
uplink0: flags=1040863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,DEPRECATED,IPv4>
mtu 1500 index 2
        inet 47.154.169.130 netmask ffffff00 broadcast 47.154.169.255
        ether 0:0:bb:2e:74:e
uplink0:1: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
mtu 1500 index 2
        inet 47.154.169.128 netmask ffffff00 broadcast 47.154.169.255
uplink0:2: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
mtu 1500 index 2
        inet 47.154.169.129 netmask ffffff00 broadcast 47.154.169.255
uplink1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3
        inet 192.168.47.1 netmask ffffff00 broadcast 192.168.47.255
        ether 0:0:bb:2e:74:d
=====
And added ip 47.154.169.128  and 47.154.169.129  into the from ip list
entry in the key file, then I push the ssh key to server
47.154.169.130 (which should be the same server as the source)
Then when I try to start the ssh connection through command ssh -I
pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 , the key does not work
anymore, and the log give info like this
==
 Authentication tried for pmcftp with correct key but not from a
permitted host (host=iems196-unit0, ip=47.154.169.130)
==
Obviously, here the from ip list does not include 47.154.169.130, and
the ssh connection treate the from ip as 47.154.169.130 not other ips
of this server.
Then I tried another command
Ssh -b 47.154.169.128  -I pmcftp -i. ./ssh/pmcftp_id_rsa
47.154.169.130 the key works well again.
The -b option is binding the from ip to 57.154.169.128 and it's in the
from ip list in the key file.

how the ip of the from side of the ssh connection is obtained? When
the from side of the ssh connection has several ips how would the ip
address be determined by the to side?
Any info would be highly appreciated, thanks in advance!

Best regards
Guang

--
徐广
13581797776

[Robert Hajime Lanning]

2009/8/21 徐广 <xuguang181@...>:
> how the ip of the from side of the ssh connection is obtained? When
> the from side of the ssh connection has several ips how would the ip
> address be determined by the to side?

This is actually system specific, not ssh.

It is the address of the outbound interface (as determined by the
routing table.)
If the outbound interface has multiple addresses, then it gets the
primary address.

--
And, did Galoka think the Ulus were too ugly to save?
                                         -Centauri

this is far from a ssh problem, as the connect src address is selected
by system, mostly by the default routing set, in your case, there are
many IP in the same vlan/ip space, that will be choosed to be the first
ip in your ip list, .130 is the first then.

you may use the "-b" option if you really need to set your src ip
address.


在 2009-08-22六的 12:10 +0800，徐广写道：

> Hi
> I recently met with a problem when trying to set up ssh connection
> through the ssh key
>
> I first create a key through command ssh-keygen -t rsa -f
> /.ssh/pmcftp_id_rsa -P "" , two files would be created under /.ssh
> pmcftp_id_rsa and pmcftp_id_rsa.pub, then I insert an entry into the
> .pub file - from="47.154.169.129,47.154.169.128"  this should
> restrickt that the ssh key should only work for sources of these two
> ips.
> Then I push the public key to another server under ~pmcftp/.ssh, after
> that, I start the ssh connection through command ssh -I pmcftp -i.
> ./ssh/pmcftp_id_rsa <server ip>, the ssh connection would be set up
> without asking for the passwd.
> But, when I create the ssh key on a server that has several ip
> address, like following:
> =====
> ifconfig -a
> lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu
> 8232 index 1
>         inet 127.0.0.1 netmask ff000000
> uplink0: flags=1040863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,DEPRECATED,IPv4>
> mtu 1500 index 2
>         inet 47.154.169.130 netmask ffffff00 broadcast 47.154.169.255
>         ether 0:0:bb:2e:74:e
> uplink0:1: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
> mtu 1500 index 2
>         inet 47.154.169.128 netmask ffffff00 broadcast 47.154.169.255
> uplink0:2: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
> mtu 1500 index 2
>         inet 47.154.169.129 netmask ffffff00 broadcast 47.154.169.255
> uplink1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3
>         inet 192.168.47.1 netmask ffffff00 broadcast 192.168.47.255
>         ether 0:0:bb:2e:74:d
> =====
> And added ip 47.154.169.128  and 47.154.169.129  into the from ip list
> entry in the key file, then I push the ssh key to server
> 47.154.169.130 (which should be the same server as the source)
> Then when I try to start the ssh connection through command ssh -I
> pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 , the key does not work
> anymore, and the log give info like this
> ==
>  Authentication tried for pmcftp with correct key but not from a
> permitted host (host=iems196-unit0, ip=47.154.169.130)
> ==
> Obviously, here the from ip list does not include 47.154.169.130, and
> the ssh connection treate the from ip as 47.154.169.130 not other ips
> of this server.
> Then I tried another command
> Ssh -b 47.154.169.128  -I pmcftp -i. ./ssh/pmcftp_id_rsa
> 47.154.169.130 the key works well again.
> The -b option is binding the from ip to 57.154.169.128 and it's in the
> from ip list in the key file.
>
> how the ip of the from side of the ssh connection is obtained? When
> the from side of the ssh connection has several ips how would the ip
> address be determined by the to side?
> Any info would be highly appreciated, thanks in advance!
>
> Best regards
> Guang
>
> --
> 徐广
> 13581797776

[徐广]

Thanks ming for your reply

When I connect to  47.154.169.130 the from ip would be
47.154.169.130, but when I try to connect to other servers, the from
ip became 47.154.169.128, so this is really refusing me.



2009/8/24 ming.zym@... <ming.zym@...>:

> this is far from a ssh problem, as the connect src address is selected
> by system, mostly by the default routing set, in your case, there are
> many IP in the same vlan/ip space, that will be choosed to be the first
> ip in your ip list, .130 is the first then.
>
> you may use the "-b" option if you really need to set your src ip
> address.
>
>
> 在 2009-08-22六的 12:10 +0800，徐广写道：
>> Hi
>> I recently met with a problem when trying to set up ssh connection
>> through the ssh key
>>
>> I first create a key through command ssh-keygen -t rsa -f
>> /.ssh/pmcftp_id_rsa -P "" , two files would be created under /.ssh
>> pmcftp_id_rsa and pmcftp_id_rsa.pub, then I insert an entry into the
>> .pub file - from="47.154.169.129,47.154.169.128"  this should
>> restrickt that the ssh key should only work for sources of these two
>> ips.
>> Then I push the public key to another server under ~pmcftp/.ssh, after
>> that, I start the ssh connection through command ssh -I pmcftp -i.
>> ./ssh/pmcftp_id_rsa <server ip>, the ssh connection would be set up
>> without asking for the passwd.
>> But, when I create the ssh key on a server that has several ip
>> address, like following:
>> =====
>> ifconfig -a
>> lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu
>> 8232 index 1
>>         inet 127.0.0.1 netmask ff000000
>> uplink0: flags=1040863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,DEPRECATED,IPv4>
>> mtu 1500 index 2
>>         inet 47.154.169.130 netmask ffffff00 broadcast 47.154.169.255
>>         ether 0:0:bb:2e:74:e
>> uplink0:1: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
>> mtu 1500 index 2
>>         inet 47.154.169.128 netmask ffffff00 broadcast 47.154.169.255
>> uplink0:2: flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
>> mtu 1500 index 2
>>         inet 47.154.169.129 netmask ffffff00 broadcast 47.154.169.255
>> uplink1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 3
>>         inet 192.168.47.1 netmask ffffff00 broadcast 192.168.47.255
>>         ether 0:0:bb:2e:74:d
>> =====
>> And added ip 47.154.169.128  and 47.154.169.129  into the from ip list
>> entry in the key file, then I push the ssh key to server
>> 47.154.169.130 (which should be the same server as the source)
>> Then when I try to start the ssh connection through command ssh -I
>> pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 , the key does not work
>> anymore, and the log give info like this
>> ==
>>  Authentication tried for pmcftp with correct key but not from a
>> permitted host (host=iems196-unit0, ip=47.154.169.130)
>> ==
>> Obviously, here the from ip list does not include 47.154.169.130, and
>> the ssh connection treate the from ip as 47.154.169.130 not other ips
>> of this server.
>> Then I tried another command
>> Ssh -b 47.154.169.128  -I pmcftp -i. ./ssh/pmcftp_id_rsa
>> 47.154.169.130 the key works well again.
>> The -b option is binding the from ip to 57.154.169.128 and it's in the
>> from ip list in the key file.
>>
>> how the ip of the from side of the ssh connection is obtained? When
>> the from side of the ssh connection has several ips how would the ip
>> address be determined by the to side?
>> Any info would be highly appreciated, thanks in advance!
>>
>> Best regards
>> Guang
>>
>> --
>> 徐广
>> 13581797776
>
>

--
徐广
13581797776

[Sharad-2]

How is your DNS setup? How does this work when you connect with hostnames instead of IP Addresses? Do other two aliases (uplink0:1 and 0:2) have same name as primary interface's?

Sharad

--- On Mon, 24/8/09, 徐广 <xuguang181@...> wrote:

> From: 徐广 <xuguang181@...>
> Subject: Re: A question about ssh RSA key connection
> To: "ming.zym@..." <ming.zym@...>
> Cc: secureshell@...
> Date: Monday, 24 August, 2009, 8:46 AM
> Thanks ming for your reply
>
> When I connect to  47.154.169.130 the from ip would
> be
> 47.154.169.130, but when I try to connect to other servers,
> the from
> ip became 47.154.169.128, so this is really refusing me.
>
>
>
> 2009/8/24 ming.zym@...
> <ming.zym@...>:
> > this is far from a ssh problem, as the connect src
> address is selected
> > by system, mostly by the default routing set, in your
> case, there are
> > many IP in the same vlan/ip space, that will be
> choosed to be the first
> > ip in your ip list, .130 is the first then.
> >
> > you may use the "-b" option if you really need to set
> your src ip
> > address.
> >
> >
> > 在 2009-08-22六的 12:10 +0800，徐广写道：
> >> Hi
> >> I recently met with a problem when trying to set
> up ssh connection
> >> through the ssh key
> >>
> >> I first create a key through command ssh-keygen -t
> rsa -f
> >> /.ssh/pmcftp_id_rsa -P "" , two files would be
> created under /.ssh
> >> pmcftp_id_rsa and pmcftp_id_rsa.pub, then I insert
> an entry into the
> >> .pub file -
> from="47.154.169.129,47.154.169.128"  this should
> >> restrickt that the ssh key should only work for
> sources of these two
> >> ips.
> >> Then I push the public key to another server under
> ~pmcftp/.ssh, after
> >> that, I start the ssh connection through command
> ssh -I pmcftp -i.
> >> ./ssh/pmcftp_id_rsa <server ip>, the ssh
> connection would be set up
> >> without asking for the passwd.
> >> But, when I create the ssh key on a server that
> has several ip
> >> address, like following:
> >> =====
> >> ifconfig -a
> >> lo0:
> flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL>
> mtu
> >> 8232 index 1
> >>         inet
> 127.0.0.1 netmask ff000000
> >> uplink0:
> flags=1040863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,DEPRECATED,IPv4>
> >> mtu 1500 index 2
> >>         inet
> 47.154.169.130 netmask ffffff00 broadcast 47.154.169.255
> >>         ether
> 0:0:bb:2e:74:e
> >> uplink0:1:
> flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
> >> mtu 1500 index 2
> >>         inet
> 47.154.169.128 netmask ffffff00 broadcast 47.154.169.255
> >> uplink0:2:
> flags=1000863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST,IPv4>
> >> mtu 1500 index 2
> >>         inet
> 47.154.169.129 netmask ffffff00 broadcast 47.154.169.255
> >> uplink1:
> flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu
> 1500 index 3
> >>         inet
> 192.168.47.1 netmask ffffff00 broadcast 192.168.47.255
> >>         ether
> 0:0:bb:2e:74:d
> >> =====
> >> And added ip 47.154.169.128  and
> 47.154.169.129  into the from ip list
> >> entry in the key file, then I push the ssh key to
> server
> >> 47.154.169.130 (which should be the same server as
> the source)
> >> Then when I try to start the ssh connection
> through command ssh -I
> >> pmcftp -i. ./ssh/pmcftp_id_rsa 47.154.169.130 ,
> the key does not work
> >> anymore, and the log give info like this
> >> ==
> >>  Authentication tried for pmcftp with correct
> key but not from a
> >> permitted host (host=iems196-unit0,
> ip=47.154.169.130)
> >> ==
> >> Obviously, here the from ip list does not include
> 47..154.169.130, and
> >> the ssh connection treate the from ip as
> 47.154.169.130 not other ips
> >> of this server.
> >> Then I tried another command
> >> Ssh -b 47.154.169.128  -I pmcftp -i.
> ./ssh/pmcftp_id_rsa
> >> 47.154.169.130 the key works well again.
> >> The -b option is binding the from ip to
> 57.154.169.128 and it's in the
> >> from ip list in the key file.
> >>
> >> how the ip of the from side of the ssh connection
> is obtained? When
> >> the from side of the ssh connection has several
> ips how would the ip
> >> address be determined by the to side?
> >> Any info would be highly appreciated, thanks in
> advance!
> >>
> >> Best regards
> >> Guang
> >>
> >> --
> >> 徐广
> >> 13581797776
> >
> >
>
>
>
> --
> 徐广
> 13581797776
>

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