SHIFT-WIKI - Sjoerd Hooft's InFormation Technology
This WIKI is my personal documentation blog. Please enjoy it and feel free to reach out through blue sky if you have a question, remark, improvement or observation. See below for the latest additions, or use the search or tags to browse for content.
Cloned SLES Virtual Machine NIC
Summary: How to change the nic back to eth0 on a SLES VM which was cloned on VMware.
Date: Around 2011
Refactor: 21 February 2025: Checked links and formatting.
After cloning a Linux VM, you might find your network interface is no longer named eth0, taking on eth1 instead. This will work and causes no functional impact, however, for several reasons you might want to change it to eth0 anyway. SLES for VMware/SLES 11 SP1, uses udev to provide persistence to various devices. While this model is a big step forward from the semi-random device name assignments of the past, one side-effect is that a new MAC address, which will happen when you clone a virtual machine, is regarded as an additional interface and not a replacement. Which means a newly-cloned SLES VM powers up with eth1 as the NIC name, and not eth0. Fortunately, this situation is easy to fix. Log into the VM and edit:
/etc/udev/rules.d/70-persistent-net.rules
Scroll down to the bottom of the line to see the configuration:
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:50:56:b9:00:33", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0" SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:50:56:b9:00:34", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
The first line contains the MAC address of the original template VM while the second line is the new MAC address for the new card.
There are two ways to fix this issue:
- Completely delete the file — it will be created again on boot and the first NIC will be assigned eth0
- Delete the line containing the old entry that references eth0 and change “eth1″ to “eth0″ in the remaining line.
Make this change before you assign IP addresses. If you already have assigned IP addresses you'll also have to edit /etc/sysconfig/network/ifcfg-eth0 and /etc/sysconfig/network/route accordingly.
Don't forget to reboot the VM and check the configuration.
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Cisco VLAN Access Lists
Summary: This post gives a basic view on how to configure access lists on VLANs on Cisco switches.
Date: Around 2017
Refactor: 20 February 2025: Checked links and formatting.
This post gives a basic view on how to configure access lists on VLANs on Cisco switches.
Cisco Syslog
Summary: How to send cisco logging to a linux syslog server.
Date: Around 2017
Refactor: 20 February 2025: Checked links and formatting.
All commands assume you've already logged on to the switch with privilege level 15 access and are already in config mode (conf t).
Cisco Serial Number
Summary: How to get the serial number of a Cisco device.
Date: Around 2010
Refactor: 21 February 2025: Checked links and formatting.
If you want/need support for your cisco devices you'll need the serial number. You can get it from the software, along with other interesting information about the device:
switch1#sh version Cisco IOS Software, C3750 Software (C3750-IPBASE-M), Version 12.2(35)SE5, RELEASE SOFTWARE (fc1) Copyright (c) 1986-2007 by Cisco Systems, Inc. Compiled Thu 19-Jul-07 19:15 by nachen Image text-base: 0x00003000, data-base: 0x01080000 ROM: Bootstrap program is C3750 boot loader BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.2(25r)SEC, RELEASE SOFTWARE (fc4) switch1 uptime is 2 years, 18 weeks, 5 days, 23 hours, 56 minutes System returned to ROM by power-on System restarted at 08:16:03 CET Thu Nov 27 2008 System image file is "flash:c3750-ipbase-mz.122-35.SE5/c3750-ipbase-mz.122-35.SE5.bin" cisco WS-C3750G-24T (PowerPC405) processor (revision N0) with 118784K/12280K bytes of memory. Processor board ID FDO1233Y2FK Last reset from power-on 1 Virtual Ethernet interface 24 Gigabit Ethernet interfaces The password-recovery mechanism is enabled. 512K bytes of flash-simulated non-volatile configuration memory. Base ethernet MAC Address : 00:23:05:30:97:58 Motherboard assembly number : 73-9679-13 Power supply part number : 341-0048-53 Motherboard serial number : FDO12660FDJ Power supply serial number : DTN1456309Z Model revision number : N0 Motherboard revision number : A0 Model number : WS-C3750G-24T-S System serial number : FDO1456Y2FK Top Assembly Part Number : 800-25325-02 Top Assembly Revision Number : A0 Version ID : V06 CLEI Code Number : COMUV10ARA Hardware Board Revision Number : 0x02 Switch Ports Model SW Version SW Image ------ ----- ----- ---------- ---------- * 1 24 WS-C3750G-24T 12.2(35)SE5 C3750-IPBASE-M Configuration register is 0xF
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