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Example of Layer 4 ACL Rules
Dell(conf)#ip access-list extended ABC
Dell(conf-ext-nacl)#permit tcp host 10.1.1.1 any eq 24
Dell(conf-ext-nacl)#deny ip any any fragment
Dell(conf-ext-nacl)
In the following example, TCP packets that are first fragments or non-fragmented from host 10.1.1.1 with TCP destination port
equal to 24 are permitted. Additionally, all TCP non-first fragments from host 10.1.1.1 are permitted. All other IP packets that are
non-first fragments are denied.
Example of TCP Packets
Dell(conf)#ip access-list extended ABC
Dell(conf-ext-nacl)#permit tcp host 10.1.1.1 any eq 24
Dell(conf-ext-nacl)#permit tcp host 10.1.1.1 any fragment
Dell(conf-ext-nacl)#deny ip any any fragment
Dell(conf-ext-nacl)
Configure a Standard IP ACL
To configure an ACL, use commands in IP ACCESS LIST mode and INTERFACE mode.
For a complete list of all the commands related to IP ACLs, refer to the Dell Networking OS Command Line Interface Reference
Guide. To set up extended ACLs, refer to Configure an Extended IP ACL.
A standard IP ACL uses the source IP address as its match criterion.
1. Enter IP ACCESS LIST mode by naming a standard IP access list.
CONFIGURATION mode
ip access-list standard access-listname
2. Configure a drop or forward filter.
CONFIG-STD-NACL mode
seq sequence-number {deny | permit} {source [mask] | any | host ip-address} [count
[byte]] [order] [fragments]
NOTE:
When assigning sequence numbers to filters, keep in mind that you might need to insert a new filter. To prevent
reconfiguring multiple filters, assign sequence numbers in multiples of five.
When you use the log keyword, the CP logs details about the packets that match. Depending on how many packets match the
log entry and at what rate, the CP may become busy as it has to log these packets’ details.
To view the rules of a particular ACL configured on a particular interface, use the show ip accounting access-list
ACL-name interface interface command in EXEC Privilege mode.
Dell#show ip accounting access-list ToOspf interface gig 1/6
Standard IP access list ToOspf
seq 5 deny any
seq 10 deny 10.2.0.0 /16
seq 15 deny 10.3.0.0 /16
seq 20 deny 10.4.0.0 /16
seq 25 deny 10.5.0.0 /16
seq 30 deny 10.6.0.0 /16
seq 35 deny 10.7.0.0 /16
seq 40 deny 10.8.0.0 /16
seq 45 deny 10.9.0.0 /16
seq 50 deny 10.10.0.0 /16
Dell#
The following example shows how the seq command orders the filters according to the sequence number assigned. In the
example, filter 25 was configured before filter 15, but the show config command displays the filters in the correct order.
Dell(conf-std-nacl)#seq 25 deny ip host 10.5.0.0 any
Dell(conf-std-nacl)#seq 15 permit tcp 10.3.0.0 /16 any
Dell(conf-std-nacl)#show config
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Access Control Lists (ACLs)
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