On Thu, 5 Nov 1998, Dr. Bill Studenmund wrote:

> I think editing /etc/services to renumber the telnet service would be a
> mistake. Either just camp telnet on another service's port, or add
> something like a "joetelnet" at a new port #.

Actually, according to the man page, telnetd looks in /etc/services and
the only reason this could is to find out what port to listen on.
(Caveat:  this is only from a "logical" perspective;  I have NOT read
the source code for telnetd!)

> I'm not sure what all uses /etc/services (other than inetd, obviously :-)
> , but have the gut instinct that changing "well-defined" values to
> non-standard ones can cause a problem. Or more accuratly, it might  cause
> one a while in the future.

At the very least, netstat reads /etc/services via getservent(3), as
does tcpdump.

> Nope, that's it. Your telnet will still be as (in)secure as before, just
> external intruders won't know where to look for it.

Yep.  I strongly recommend using ssh if you want security, and disable
telnet as well as all the r things (rlogin, rsh, rcmd).


-----------------------------------------------------------------------------
| Paul Goyette      | PGP DSS Key fingerprint:   | E-mail addresses:        |
| Network Engineer  |   BCD7 5301 9513 58A6 0DBC |  paul@whooppee.com       |
| and kernel hacker |   91EB ADB1 A280 3B79 9221 |  paul.goyette@ascend.com |
-----------------------------------------------------------------------------