strange requests from Vanguard Securities: 53,137,138

[George <GeorgeZweistein@gmail.com>]

In browsing vanguard.com I find it slow, also they cause unexpected 
logging in my /var/log/messages file.  To kill these I updated itpables 
to open said ports.

#!/bin/sh
# /opt/sbin/ziptables.vanguard input
#
 iptables -I INPUT -j ACCEPT -s 167.206.251.0/24 -p udp \
 -m multiport --ports 53,137,138
#
iptables -L

Why are they examining these ports?  No one else is.

Using a Thinkpad behind a router and my own iptables firewall.  Debian 
Test and Sid environments.