Windows Update not working with ACL

Unanswered Question
Aug 17th, 2010
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Hi,


We have a vlan that we protect from inbound traffic:



   10 permit tcp any any established (189 matches)

    20 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq 554

    30 permit udp any xxx.xxx.xxx.xxx 0.0.0.1 eq 5004

    40 permit udp any xxx.xxx.xxx.xxx 0.0.0.1 eq 5005

    50 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq 1755

    60 permit udp any xxx.xxx.xxx.xxx 0.0.0.1 eq 1755

    70 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq www

    80 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq 8080

    90 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq 443

    100 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq ftp

    110 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 eq ftp-data

    120 permit tcp any xxx.xxx.xxx.xxx 0.0.0.1 gt 1024

    130 permit tcp xxx.xxx.xxx.xxx 0.0.3.255 xxx.xxx.xxx.xxx 0.0.0.1 eq 3389

    140 permit udp xxx.xxx.xxx.xxx 0.0.3.255 xxx.xxx.xxx.xxx 0.0.0.1 eq 3389

    150 deny ip any any (948 matches)


Why does windowsupdate not work? The established statement should work...


thx,


Marc

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Kureli Sankar Sat, 08/21/2010 - 15:32
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  • Cisco Employee,

Interesting..


established

(Optional) For the TCP protocol only:  Indicates an established connection. A match occurs if the TCP datagram  has the ACK or RST control bits set. The nonmatching case is that of the  initial TCP datagram to form a connection.


With the above said. If you capture on the PC that is trying to get windows update and at the same time watch the logs on the router and see what packets are being dropped.  If these are packets with ACK or RST bit set and they are from the same IP address that the client tried to talk to then, there is a problem with established command.


My thinking is that there is a new connections that is coming inbound and it does not have ACK bit set and that is the reason that established command isn't working. But, we need to see some data to be able to say it for sure.


-KS

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