Re: Killing NT 4.0's Name Server

Rubens Kuhl Jr. (rkuhljr@PUERIDOMUS.BR)
Mon, 26 May 1997 22:17:22 -0300

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Most NT 4.0 boxes doesn't listen to tcp port 19, chargen, unless the
administrator has installed "Small TCP/IP services" or such, which isn't a
default option.

But if MS DNS crashes just by sending a continuos stream of the ASCII set,
this can be easily done on a script, with no need to get it from the host
itself.

Workaround #1: block port tcp/53 on the security panel of TCP/IP. No more
zone transfers, no more TCP name resolutions (very rare), everyday UDP
resolution still works.

Workaround #2: filter port tcp/53 on the boundary router, allowing only
secondary servers to do zone transfers.

Workaround #3: install BIND.

Rubens Kuhl Jr.

----------
| $ telnet ntbox 19 | telnet ntbox 53
|
| Tested on NT 4.0 with service pack #3.
|
| Hello Dr. Watson, goodbye Mr. Nameserver.

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