Configuring IP Session Filtering (Reflexive Access Lists)

From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Fri Nov 18 2005 - 15:40:34 GMT-3


Hello All..

In Link
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fsecu
r_c/ftrafwl/scfreflx.htm

Show a Internal Interface Configuration Example that permits BGP to be passed
without been checked by the evaluate tcptraffic

*********************
Internal Interface Configuration Example
interface Ethernet 0

 description Access from the I-net to our Internal Network via this interface
 ip access-group inboundfilters in
 ip access-group outboundfilters out
!
ip reflexive-list timeout 120
!
ip access-list extended outboundfilters
 permit bgp any any
 permit eigrp any any
 deny icmp any any
 evaluate tcptraffic
!
ip access-list extended inboundfilters
 permit tcp any any reflect tcptraffic

***********************************

I do not know if it's a Typo but my router does not have BGP in the permit
options!!!

Router(config-ext-nacl)#permit ?
  <0-255> An IP protocol number
  ahp Authentication Header Protocol
  eigrp Cisco's EIGRP routing protocol
  esp Encapsulation Security Payload
  gre Cisco's GRE tunneling
  icmp Internet Control Message Protocol
  igmp Internet Gateway Message Protocol
  ip Any Internet Protocol
  ipinip IP in IP tunneling
  nos KA9Q NOS compatible IP over IP tunneling
  ospf OSPF routing protocol
  pcp Payload Compression Protocol
  pim Protocol Independent Multicast
  tcp Transmission Control Protocol
  udp User Datagram Protocol

My IOS Version is 12.2(15)T16

I think that if you like to permit bgp then this command should be used
permit tcp any eq bgp any
permit tcp any any eq bgp

Any Suggestion
Thanks



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