seq (rules in IPv4 extended bACLs)

Inserts filtering rules in IPv4 extended ACLs crafted as IP broadcast ACLs (bACLs).

Syntax

seq seq-value { permit | deny } ip-protocol { S_IPaddress mask | host S_IPaddress | any } [ source-operator [ S_port-numbers ] ] [ TCP-flags ] [ vlan vlanID ] [ count ] [ fragment | non-fragment ]
no seq seq-value
{ permit | deny } ip-protocol { S_IPaddress mask | host S_IPaddress | any } [ source-operator [ S_port-numbers ] ] [ TCP-flags ] [ count ] [ vlan vlanID ] [ fragment | non-fragment ]
no { permit | deny } ip-protocol { S_IPaddress mask | host S_IPaddress | any } [ source-operator [ S_port-numbers ] ] [ TCP-flags ] [ vlan vlanID ] [ count ] [ fragment | non-fragment ]

Parameters

seq
(Optional) Enables you to assign a sequence number to the rule. If you do not specify seq seq-value, the rule is added at the end of the list.
seq-value
Valid values range from 1 through 65535.
permit
Specifies rules to permit traffic.
deny
Specifies rules to deny traffic.
hard-drop
For bACLs, equivalent to deny.
ip-protocol
Indicates the type of IP packet you are filtering. The options are as follows:
<0-255>
Protocol number custom value from 0 through 255.
icmp
Internet Control Message Protocol
ip
Any IP protocol
tcp
(Supported only if the containing ACL is applied to incoming traffic) Transmission Control Protocol
udp
User Datagram Protocol
S_IPaddress
Specifies a source address for which you want to filter the subnet.
mask
Defines a mask, whose effect is to specify a subnet that includes the source address that you specified. For options to specify the mask, see the Usage Guidelines.
host
Specifies a source address.
S_IPaddress
The source address.
any
Specifies all source addresses.
source-operator
If you specified tcp or udp ip-protocol, the following optional operators are available:
eq
The policy applies to the TCP or UDP port name or number you enter after eq.
gt
The policy applies to TCP or UDP port numbers equal to or greater than the port number or the numeric equivalent of the port name you enter after gt.
lt
The policy applies to TCP or UDP port numbers that are equal to or less than the port number or the numeric equivalent of the port name you enter after lt.
neq
The policy applies to all TCP or UDP port numbers except the port number or port name you enter after neq.
range
The policy applies to all TCP or UDP port numbers that are between the first TCP or UDP port name or number and the second one you enter following the range keyword. The range includes the port names or numbers you enter. For example, to apply the policy to all ports between and including 23 (Telnet) and 53 (DNS), enter the following: range 23 53 (two values separated by a space). The first port number in the range must be lower than the last number in the range.
S_port-numbers
(Valid only when ip-protocol is UDP or TCP) Specifies one or more source or destination port numbers.
vlan vlanID
Specifies a VLAN interface to which the ACL is bound.
TCP-flags
If you specify tcp ip-protocol, one or more of the following flags are available:
ack
Filters packets for which the ack (acknowledge) flag is set.
fin
Filters packets for which the fin (finish) flag is set.
rst
Filters packets for which the rst (reset) flag is set.
sync
Filters packets for which the syn (synchronize) flag is set.
urg
Filters packets for which the urg (urgent) flag is set.
push
Filters packets for which the psh (push) flag is set.
count
Enables statistics for the rule.
log
Not supported for bACLs.
mirror
Not supported for bACLs.
copy-sflow
Not supported for bACLs.
fragment
Filter fragmented packets. This keyword and non-fragment keyword cannot be used together.
non-fragment
Filter non-fragmented packets. This keyword and fragment keyword cannot be used together.

Modes

ACL configuration mode

Usage Guidelines

This topic describes filtering rules in an extended IPv4 ACL intended for use as an IP broadcast ACL (bACL).

Broadcast ACLs are not supported on SLX 9150 or SLX 9250 devices.

The order of the rules in an ACL is critical, as the first matching rule stops further processing. When creating rules, specifying sequence values determines the order of rule processing. If you do not specify a sequence value, the rule is added to the end of the list.

You can specify a mask in either of the following ways:
  • Wildcard mask format—for example, 0.0.0.255. The advantage of this format is that it enables you mask any bit, for example by specifying 0.255.0.255.
  • Classless Interdomain Routing (CIDR) format—in which you specify the number of bits of the prefix. For example, appending /24 to an IPv4 address is equivalent to specifying 0.0.0.255 as wildcard mask format.
To delete a rule from an ACL, do the relevant of the following:
  • If you know the rule number, enter no seq seq-value.
  • If you do not know the rule number, type no followed by the full syntax without seq seq-value.

Filtering fragmented or non-fragmented packets is only supported on ingress ACLs. On the SLX 9540 and SLX 9640, fragment match is only supported on BGP FS profile. This ACL can also be used with RACL, PBR, and RL. Do not use Layer-4 matching along with fragment matching. Fragmented packets might not have Layer-4 information and most likely cause issues. ACL filtering of fragmented and non-fragmented packets is not supported on SLX 9150 and SLX 9250 devices.

Examples

The following example creates an IPv4 extended bACL, defines rules for it, and applies the bACL to an interface.

device# configure
device(config)# ip access-list extended bACL_ext_12
device(conf-ipacl-ext)# seq 5 deny tcp host 10.24.26.145 any eq 23
device(conf-ipacl-ext)# seq 7 deny tcp any any eq 80
device(conf-ipacl-ext)# seq 10 deny udp any any range 10 25
device(conf-ipacl-ext)# seq 15 permit tcp any any
device(conf-ipacl-ext)# exit
device(config)# interface ethernet 0/6
device(conf-if-eth-0/6)# ip subnet-broadcast-acl bACL_ext_12

The following example creates an IPv4 extended bACL, defines rules for it, and applies the bACL at device level.

device# configure
device(config)# ip access-list extended bACL_ext_22
device(conf-ipacl-ext)# seq 5 deny tcp host 10.24.26.145 any eq 23
device(conf-ipacl-ext)# seq 7 deny tcp any any eq 80
device(conf-ipacl-ext)# seq 10 deny udp any any range 10 25
device(conf-ipacl-ext)# seq 15 permit tcp any any
device(conf-ipacl-ext)# exit
device(config)# ip global-subnet-broadcast-acl bACL_ext_22