SSH question

[Lopez, Denise]

Thank you everyone for your suggestions and input. 

 

So just to clarify, the answer to my question would be that the
/etc/nsswitch.conf file tells the Linux box how to resolve IP addresses.
Mine says "hosts: files dns."  So the Linux box consults "/etc/hosts"
for the IP to name resolution and if not found consults the dns server
listed in "/etc/resolve.conf".  

 

After it has resolved the name then the packets get sent to SSH?  If
there is no name that resolves then the IP address gets passed so there
is no problem.

 

Then is the order name resolution, iptables, then ssh if it is an ssh
packet?

 

Denise Lopez

 

 

From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Richard
Riley
Sent: Thursday, October 25, 2007 12:55 PM
To: redhat-sysadmin-list at redhat.com
Subject: RE: SSH question

 

Denise,

 

If the windows machines do have static IP addresses, you can eliminate
the need to worry about AD or BIND by simply adding entries on the
servers in "/etc/hosts" for the windows machines.  This way, you control
the hostname that will match the IP address and thus control what
hostname to use in your sshd_config entries.

 

Richard Riley
System Administrator
Email: rriley at procuri.com <mailto:rgambotz at procuri.com> 

Procuri Inc.
www.procuri.com <http://www.procuri.com> 

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From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Lopez,
Denise
Sent: Thursday, October 25, 2007 2:56 PM
To: redhat-sysadmin-list at redhat.com
Subject: RE: SSH question

 

Thanks Jonathan,

 

We are running AD and BIND.  The windows clients look to AD for DNS.
Our AD hosts our internal DNS and BIND hosts external DNS.  The SSH
server also looks to AD for DNS.  For one admin station there is only a
DNS entry in AD and the other one there is a DNS entry in AD and an A
record but no PTR record in BIND.

 

My Linux box has NO entry in AD or in BIND so the IP address doesn't
resolve and there is no problem. I guess then my question is how does
SSH handle DNS lookups?

 

Denise Lopez

 

 

From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Martin,
Jonathan
Sent: Thursday, October 25, 2007 5:47 AM
To: redhat-sysadmin-list at redhat.com
Subject: RE: SSH question

 

DHCP and "Register this connection in DNS" are separate.  You can
specify static IPs in Windows and still have the server dynamically
register itself in DNS.  The difference is with DHCP the DHCP server
(can) register the client's HOST record in DNS, but the client still
dynamically registers its PTR.  Are you running Active Directory and
BIND?  If your windows clients look to Windows for DNS and your SSH
server looks to BIND then you might have an issue of host and PTR
records not being in the right DNS.

 

-Jonathan

 

________________________________

From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Holder,
Bill
Sent: Wednesday, October 24, 2007 7:47 PM
To: redhat-sysadmin-list at redhat.com
Subject: RE: SSH question

Hi there,

 

    you need to setup the dynamic DNS support in your DHCP client on
your Redhat boxes. I'm sorry I can't be more specific, it's been a while
since I did it, but I'm sure Google will point you at the information
you need.

 

 

/B

 

 

________________________________

From: redhat-sysadmin-list-bounces at redhat.com
[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf Of Lopez,
Denise
Sent: Thursday, 25 October 2007 9:44 AM
To: redhat-sysadmin-list at redhat.com
Subject: RE: SSH question

Thanks for your reply Richard,

 

The windows boxes are using DHCP but they have static DHCP reservations
because they are administrative boxes so they always get the same IP
address.  

 

I think it has something to do on the RHEL side and am just not sure
what is happening.

 

Denise Lopez

 


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