Restrict access to port 23 to only those fixed IPs on the firewall, and
block to all other IPs?


mside wrote:
> Is there a way to determine when a user is logging in whether the user
> is using 'telnet' or 'ssh'?
>
> We want to limit access to telnet to certain fixed IP address which are
> local 'ethernet' terminals.
> I also would like to keep my PROCOMM Plus software working.
>
> Thanks,
>
> Denny Watkins
> Morningside College
>
> Phone: 712-274-5250
>
> Email: watkins@morningside.edu

Access can be limited by using IP filtering which will allow certain IP
address to access the server while the rest would be restricted. PLS
NOTE that extra care and good understanding of IP filtering is required
while doing this as you might end up restricting all IPs and hence
prevent logins for all.

HTH

mside wrote:
> Is there a way to determine when a user is logging in whether the user
> is using 'telnet' or 'ssh'?
>
> We want to limit access to telnet to certain fixed IP address which are
> local 'ethernet' terminals.
> I also would like to keep my PROCOMM Plus software working.
>
> Thanks,
>
> Denny Watkins
> Morningside College
>
> Phone: 712-274-5250
>
> Email: watkins@morningside.edu

Telnet is easy to restrict. It runs from inetd. You can add a
tcpwrapper to it to prevent unauthorized IP addresses from even reaching
telnetd.

Roy

Ashok Sangra wrote:
> Access can be limited by using IP filtering which will allow certain IP
> address to access the server while the rest would be restricted. PLS
> NOTE that extra care and good understanding of IP filtering is required
> while doing this as you might end up restricting all IPs and hence
> prevent logins for all.
>
> HTH
>
> mside wrote:
>> Is there a way to determine when a user is logging in whether the user
>> is using 'telnet' or 'ssh'?
>>
>> We want to limit access to telnet to certain fixed IP address which are
>> local 'ethernet' terminals.
>> I also would like to keep my PROCOMM Plus software working.
>>
>> Thanks,
>>
>> Denny Watkins
>> Morningside College
>>
>> Phone: 712-274-5250
>>
>> Email: watkins@morningside.edu
>

a ps will show as well. I think telnet and ssh each should show a PID
for each session.

mside wrote:
> Is there a way to determine when a user is logging in whether the user
> is using 'telnet' or 'ssh'?
>
> We want to limit access to telnet to certain fixed IP address which are
> local 'ethernet' terminals.
> I also would like to keep my PROCOMM Plus software working.
>
> Thanks,
>
> Denny Watkins
> Morningside College
>
> Phone: 712-274-5250
>
> Email: watkins@morningside.edu
>

>>> We want to limit access to telnet to certain fixed IP address which are
>>> local 'ethernet' terminals.

tcp wrappers can accomplish this .. google for it ..

HTH
Mark Taylor

Aixers,

Thank you for the many good suggestion on how to
limit access to telnet to certain fixed IP address.

We are currently running AIX 5.3.

tcp_wrapper 7.6.1.0 is available from a few sites like

www.bullfreeware.com and
ftp://ftp.porcupine.org/pub/security/index.html

Is this the latest version and can I install it on AIX 5.3?

Thanks Again

Denny Watkins

mside wrote:
m> Aixers,
m>
m> Thank you for the many good suggestion on how to
m> limit access to telnet to certain fixed IP address.
m>
m> We are currently running AIX 5.3.
m>
m> tcp_wrapper 7.6.1.0 is available from a few sites like
m>
m> www.bullfreeware.com and
m> ftp://ftp.porcupine.org/pub/security/index.html
m>
m> Is this the latest version and can I install it on AIX 5.3?
m>
m> Thanks Again
m>
m> Denny Watkins

Yep, good things don't need to change a lot...

Just as a side note, the source compiles fine on 5.3 and if you want to
control ssh access as well, you need to roll your own sshd w/ libwrap.a.

I use it on 5.3 to curb pesky brute force ssh probes. Works like a champ!

In article ,
Bela wrote:

> mside wrote:
> m> Aixers,
> m>
> m> Thank you for the many good suggestion on how to
> m> limit access to telnet to certain fixed IP address.
> m>
> m> We are currently running AIX 5.3.
> m>
> m> tcp_wrapper 7.6.1.0 is available from a few sites like
> m>
> m> www.bullfreeware.com and
> m> ftp://ftp.porcupine.org/pub/security/index.html
> m>
> m> Is this the latest version and can I install it on AIX 5.3?
> m>
> m> Thanks Again
> m>
> m> Denny Watkins
>
> Yep, good things don't need to change a lot...
>
> Just as a side note, the source compiles fine on 5.3 and if you want to
> control ssh access as well, you need to roll your own sshd w/ libwrap.a.
>
> I use it on 5.3 to curb pesky brute force ssh probes. Works like a champ!

You can also type 'whodo' at the prompt. It shows how the connection was
made and what the user is doing.