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This is a small technical question. I can't seem to find any information on this, so I thought I'd ask here.

I'm currently studying for my CCNA and I'm currently on the topic of ACLs. On IOS standard numbered ACLs go from 1 to 99 and then additional standard ACL numbering is from 1300 to 1999. For the extended ACL the numbering is from 100 to 199 and then from 2000 to 2699.

The question is, what's up with the gap? I haven't found any information about it but I'm just wondering - why? Is there a reason for this or did Cisco just use arbitrary numbers here.

Is there a reason why there is a gap from 200 to 1300.

Thanks!

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1 Answer 1

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Over the years, Cisco has supported various protocols, and has had ACLs for the various protocols, each with a number range for the numbered ACLs (today, we mostly use named ACLs)*:

+-----------------------------------------------------+-----------------------+
| Protocol                                            | Range                 |
+-----------------------------------------------------+-----------------------+
| Standard IP                                         | 1–99 and 1300–1999    |
| Extended IP                                         | 100–199 and 2000–2699 |
| Ethernet type code                                  | 200–299               |
| DECnet and extended DECnet                          | 300–399               |
| Xerox Network Systems (XNS)                         | 400–499               |
| Extended XNS                                        | 500–599               |
| AppleTalk                                           | 600–699               |
| Ethernet address                                    | 700–799               |
| Internetwork Packet Exchange (IPX)                  | 800–899               |
| Extended IPX                                        | 900–999               |
| IPX Service Advertising Protocol (SAP)              | 1000–1099             |
| Transparent bridging (protocol type)                | 200–299               |
| Transparent bridging (vendor code)                  | 700–799               |
| Extended transparent bridging                       | 1100–1199             |
| Source-route bridging (protocol type)               | 200–299               |
| Source-route bridging (vendor code)                 | 700–799               |
| Standard Virtual Integrated Network Service (VINES) | 1–100                 |
| Extended VINES                                      | 101–200               |
| Simple VINES                                        | 201–300               |
+-----------------------------------------------------+-----------------------+

*(The table was recreated from a PDF circa 2001, but the PDF table appears to be identical to a table from the Cisco Press article, Basic Access List Configuration for Cisco Devices, circa 2011. It is quite possible that both tables were authored by the same person. Unfortunately, I do not have the author information for the PDF.)

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