How to open a port in Redhat 8.0

Hi all,

I am trying to setup openssh in redhat 8.0. I am not using any firewall
(iptables or ipchains).

I am not able to access data center system using openssh from
homeoffice. with nmap it is not showing port 22 as open. I have been
searching on internet but could not find how to open port 22. some
replies were suggeseting to use iptables to open but i have disabled
iptalbles on this machine. i am able to get that first time ssh login
message when i try within LAN at datacenter.

Any help is greatly appreciated.

"Linux_Newbie" <skshukla@hotmail.com> wrote in message
news:E3vgb.55983$%h1.42025@sccrnsc02...
> Hi all,
>
> I am trying to setup openssh in redhat 8.0. I am not using any firewall
> (iptables or ipchains).
>
> I am not able to access data center system using openssh from
> homeoffice. with nmap it is not showing port 22 as open. I have been
> searching on internet but could not find how to open port 22. some
> replies were suggeseting to use iptables to open but i have disabled
> iptalbles on this machine. i am able to get that first time ssh login
> message when i try within LAN at datacenter.

The problem is probably not at the Linux-box. Do you have a firewall
shielding your datacenter from the internet, and thereby your home office?
Ask your network administrator if he can/will open it for ssh traffic to
pass.

Regards
Carsten Keller

Thanks Carsten for your reply. There is no firewall shielding on either
side as i am able to connect to other server from same data Center LAN.
This server has port 22 open as seen in nmap on this server.

So there has to be some way to open port 22 on other server so that i
can access openssh.

Carsten Keller wrote:

> "Linux_Newbie" <skshukla@hotmail.com> wrote in message
> news:E3vgb.55983$%h1.42025@sccrnsc02...
>
>>Hi all,
>>
>>I am trying to setup openssh in redhat 8.0. I am not using any firewall
>>(iptables or ipchains).
>>
>>I am not able to access data center system using openssh from
>>homeoffice. with nmap it is not showing port 22 as open. I have been
>>searching on internet but could not find how to open port 22. some
>>replies were suggeseting to use iptables to open but i have disabled
>>iptalbles on this machine. i am able to get that first time ssh login
>>message when i try within LAN at datacenter.
>
>
> The problem is probably not at the Linux-box. Do you have a firewall
> shielding your datacenter from the internet, and thereby your home office?
> Ask your network administrator if he can/will open it for ssh traffic to
> pass.
>
> Regards
> Carsten Keller
>
>

"Linux_Newbie" <skshukla@hotmail.com> wrote in message
news:DSwgb.703794$uu5.116141@sccrnsc04...
> Thanks Carsten for your reply. There is no firewall shielding on either
> side as i am able to connect to other server from same data Center LAN.
> This server has port 22 open as seen in nmap on this server.
>
> So there has to be some way to open port 22 on other server so that i
> can access openssh.

I'm not sure what you mean. Is this correct:
You want to use a ssh-client from your homenetwork to connect to a
ssh-server at the data-center.
There's no firewall protecting your datacenter-LAN from the internet.
You have no firewall protecting your home-office.
You can connect with a ssh-client on Datacenter-LAN to the server.

Can you reach any other services from home to the data-center? Ping, www,
mail etc.?

Regards
Carsten Keller

> > "Linux_Newbie" <skshukla@hotmail.com> wrote in message
> > news:E3vgb.55983$%h1.42025@sccrnsc02...
> >
> >>Hi all,
> >>
> >>I am trying to setup openssh in redhat 8.0. I am not using any firewall
> >>(iptables or ipchains).
> >>
> >>I am not able to access data center system using openssh from
> >>homeoffice. with nmap it is not showing port 22 as open. I have been
> >>searching on internet but could not find how to open port 22. some
> >>replies were suggeseting to use iptables to open but i have disabled
> >>iptalbles on this machine. i am able to get that first time ssh login
> >>message when i try within LAN at datacenter.
> >
> >
> > The problem is probably not at the Linux-box. Do you have a firewall
> > shielding your datacenter from the internet, and thereby your home office?
> > Ask your network administrator if he can/will open it for ssh traffic to
> > pass.
> >
> > Regards
> > Carsten Keller
> >
> >

Agreed. Assuming sshd is running, then if you cannot access port 22
something is preventing this. You have stated that the server has no
firewall running - your data center will have one (or more) though.
Talk to the support staff there and ensure that they have enabled
remote access for you.