udp port 135

[cc <cc@belfordhk.com>]

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Hi,

Can someone comment on the following script as to whether or not
it should work?  (It's related of course to the influx of 135
scans..)

iptables -A INPUT -i $EXT_DEV -p tcp -d $EXT_DEV --dport 135 -j DROP
iptables -A INPUT -i $EXT_DEV -p udp -d $EXT_DEV --dport 135 -j DROP

iptables -A OUTPUT -o $EXT_DEV -p tcp -d $EXT_DEV --dport 135 -j DROP
iptables -A OUTPUT -o $EXT_DEV -p udp -d $EXT_DEV --dport 135 -j DROP

Perhaps my understand of UDP packets isn't very deep, so I
might have missed some tidbit regarding the states of udp ports.

But with the above script portion, when I execute:

nmap -sT -p 135 <ext ip>

from a remote machine, I get a host down message. With

nmap -sT -P0 -p 135 <ext ip>,

I get a (135/tcp filtered).  (Good news?)

But with :

nmap -sU -P0 -p 135 <ext ip>,

I get a (135/udp open).

Can someone explain to me what I'm doing wrong or what
information I have forgotten?    Does it even matter
if the udp 135 port is open?  I'm currently in
the process of closing all unneccessary ports
(be it tcp or udp).

Thanks.








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