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unknown hostname

Posted on 2004-11-24
Medium Priority
Last Modified: 2013-12-16 (i am sure it is correct) is the ip address of the machine i put red hat 9.0 on it. but i cannot ssh to. its saying host/servername not known. What should do
Question by:komlaaa

Author Comment

ID: 12672273
sorry if i did not make myself clear enough.
i am able to ssh from machine with ip address BUT not to it.
In another seems unknown from outside.
LVL 88

Expert Comment

ID: 12673402
either your SSH Daemon isn't running on that machine or your firewall settings are blocking port 22.

Expert Comment

ID: 12678901
I am going to assume this is a box on a cable modem. If this is the case you need a dynamic DNS client (www.dyndns.org) to one make the machine accessible from the Internet. Two as mentioned above  by rindi you need to make sure if you have a router in front of the box that it allows SSH connections through from the Internet. Then you should be all set because all default SSH installs will allow connections from (i.e anywhere). Hope this helps.


Expert Comment

ID: 12678911
I need to ammend my above statement: "If this is the case you need a dynamic DNS client (www.dyndns.org) to one make the machine accessible from the Internet" It should read "If this is the case you need a dynamic DNS client (www.dyndns.org) to one make the machine accessible from the Internet by hostname otherwise you can continue to access by IP, provided your IP does not change.

LVL 38

Accepted Solution

wesly_chen earned 500 total points
ID: 12682676
For RedHat Linux 9, login as root
# service sshd start    <=== start sshd
# chkconfig --level 2345 sshd on  <=== turn on sshd at boot time

> seems unknown from outside.
Your machine is not registered in your DNS domain, ask your sysadm or network administrator to add
your hostname and IP address into your company's DNS.
Before that, try "ssh" from other machine first.


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