Differences

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--- os:ios:vlan.dat [2016-11-20 00:37] – root
+++ os:ios:vlan.dat [2023-01-03 12:36] – Manuel Frei
@@ Line 1: / Line 1: @@
 ====== vlan.dat ======
+I wrote a Python module/utility to parse vlan.dat files: https://github.com/frei-style/vlandat
+This page shows some information about the reverse engineering.
 ===== About the File =====
@@ Line 22: / Line 26: @@
   * [[http://www.cisco.com/c/en/us/support/docs/switches/catalyst-2940-series-switches/109304-manage-vlandat.html|Managing vlan.dat in Cisco Catalyst Switches Running Cisco IOS Software]]
+===== Influence of VTP Configuration =====
+>In VTP Server Mode, switch "saves VLAN configuration information in a file named vlan.dat in flash memory."
+>In VTP Client Mode, switch saves "VLAN information in RAM only, not stored in NVRAM or FLash memory; must be repopulated from a VTP server if switch is power-cycled."
+>In VTP Transparent Mode, switch saves VLAN configuration in NVRAM.
+//-- SWITCH (642-813) Student Guide Volume I//
 ===== Structure =====
@@ Line 35: / Line 49: @@
 | 00a    | 32    | string  | VTP Domain Name          | ascii, 0-32 chars | -                    |
 | 02a    | 2     | :?:     | :?:                      | ? | |
-| 02c    | 4     | int     | Configuration Revision   | <nowiki>0-2^31</nowiki> | <del>this may is only 4 bytes, like in the VTP network package</del> |
+| 02c    | 4     | int     | Configuration Revision   | <nowiki>0-2^31</nowiki> | <del>this may is only 4 bytes, like in the VTP network package</del> //Max revision number is 2,147,483,648then counter will reset back to zero// -- [[https://www.coursehero.com/file/p6k41no/Max-revision-number-is-2147483648-then-counter-will-reset-back-to-zero-VLAN/|source]] |
 | 030    | 4     | int     | Local updater ID         |  | IP address        |
 | 034    | 4     | int     | Last update on           |  | vlan interface with lowest number. :?: this may is only 2 bytes |
@@ Line 66: / Line 80: @@
 | 0d9    | 1     | char    | Backup CRF Mode | 0 (disabled), 1 (enabled) | type must be trcrf |
 | 0da    | 1     | char    | Remote SPAN | 0 (disabled), 1 (enabled) | |
-| 0db    | 1     | char    | :?:         | :?:  | :?: I have no idea. I changed the value to 1 and 2 but I didn't notice some differences on the switch with the show command. |
+| 0db    | 1     | char    | :?:         | :?:  | :?: I have no idea. I changed the value to 1 and 2 but I didn't notice any differences on the switch with the show command. |
 ^ Following Stuff is yet unknown ^^^^^^
 | ...    | :?:   | :?:     | :?: | :?: | :?: Looks like garbage, will be harder to figure that out. |
@@ Line 156: / Line 170: @@
 === Garbage ===
-There is some garbage at the end of the file. Marco Rizzi ([[http://rizzitech.blogspot.ch/2010_08_01_archive.html|Playing with vlan.dat]]) assumes, that it's additional information about FDDI/Token Ring vlans. I think he's right.
+There is some garbage at the end of the file. Marco Rizzi ([[http://rizzitech.blogspot.ch/2010_08_01_archive.html|Playing with vlan.dat]], the blog post was deleted unfortunately. It's available via Web Archive: [[https://web.archive.org/web/20150115040419/http://rizzitech.blogspot.com/2010/08/playing-with-vlandat.html|WebArchive]]) assumes, that it's additional information about FDDI/Token Ring vlans. I think he's right.
 I deleted the vlan.dat and reloaded the switch to get this clean config: