(TIL) Today I Learned...

Started by Seittit, January 13, 2015, 03:50:21 AM

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wintermute000

#240
August 11, 2016, 10:45:22 PM
that website check is the SOP when parsing for hires. Faster than asking the guy to provide evidence....

deanwebb

#241
September 09, 2016, 08:27:54 AM
TIL how to
Code Select
sudo

:badass:
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

SimonV

#242
February 08, 2017, 04:39:38 AM
TIL that Sonos audio players participate in STP and build wireless links between devices  :eek:

https://en.community.sonos.com/troubleshooting-228999/sonos-and-the-spanning-tree-protocol-16973

deanwebb

#243
February 08, 2017, 10:30:30 AM
Quote from: SimonV on February 08, 2017, 04:39:38 AM
TIL that Sonos audio players participate in STP and build wireless links between devices  :eek:

https://en.community.sonos.com/troubleshooting-228999/sonos-and-the-spanning-tree-protocol-16973



So, in spite of the fact that BPDU guard is used for some very good reasons on switch ports, these guys want us to turn it off so we can all listen to the music together.

Why couldn't they come up with a proprietary solution that doesn't break BPDU guard?
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

SimonV

#244
February 08, 2017, 03:48:02 PM
Indeed, had some issues at a company where they were installing these. First with BPDUguard, then with the link costs after removing BPDUguard. Wouldn't have expected this on a 'consumer' product but thank god it's just standard STP so it wasn't too hard to get it contained. But imagine what would happen if two of these speakers are installed in different VLANS and then team up.

:whatudo:

deanwebb

#245
February 08, 2017, 06:14:34 PM
... and one has a magic MAC address and takes over as the master...
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

mlan

#246
February 09, 2017, 04:17:26 PM Last Edit: February 10, 2017, 04:15:11 PM by mlan
Quote from: SimonV on February 08, 2017, 04:39:38 AM
TIL that Sonos audio players participate in STP and build wireless links between devices  :eek:

I just ran into a similar situation this week.  A contractor was installing a Crestron audio control system, and after they tripped bpduguard on multiple ports, we discovered the panel they are installing has an "embedded switch" that is running RSTP right out of the box.  Check out this quote from the manual:

QuotePrior to 2012, every digital media (DM) card and endpoint in an installation required its own IP address on the corporate network.  In 2012, Crestron introduced private network mode (PNM) to DM switchers. PNM greatly reduces the number of IP addresses required for DM installations. Crestron recommends using PNM to manage Ethernet settings for DM cards and endpoints connected to a DM switcher. Other methods are not recommended.

Nice...

http://www.crestron.com/downloads/pdf/product_misc/dg_ip-considerations-guide-it-professional.pdf

deanwebb

#247
February 10, 2017, 07:50:26 AM
Cool. IPvCrestron.
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

deanwebb

#248
March 22, 2017, 07:24:44 AM
My TIL for yesterday was that layer 2 fallback on a TippingPoint IPS isn't always a layer 2 fallback. It's supposed to be a state in which the IPS doesn't do anything to the traffic, but yesterday I saw it one in fallback that was still affecting traffic.

My IPS in layer 2 fallback was doing this: :umad:

Putting the entire segment into bypass mode instead was what worked to have the IPS not affect the traffic.

So, if you have an IPS, and you tested it in layer 2 fallback... test it again.
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

deanwebb

#249
July 10, 2017, 12:12:09 PM
TIL about ssh -v -v -v -v

Pretty cool stuff, ran it on the box that was closing connection and on one that wasn't to do a compare. The first box seems to not be accepting the public key of the management box, and it's happening right after an upgrade we did yesterday... hmmm...
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

Otanx

#250
July 10, 2017, 03:09:03 PM
"ssh -v -v -v -v" can be shortened to "ssh -vvvv" Most commands will accept multiple switches after a single - unless they need a value supplied. As an example

"tcpdump -n -n -i eth0" can be shortened to "tcpdump -nni eth0"

If you need more than one switch to accept a value you can still consolidate except for the ones that need values.

"tcpdump -n -n -i eth0 -w capture.pcap" can be shortened to "tcpdump -nni eth0 -w capture.pcap"

-Otanx

deanwebb

#251
July 10, 2017, 04:27:48 PM
Quote from: Otanx on July 10, 2017, 03:09:03 PM
"ssh -v -v -v -v" can be shortened to "ssh -vvvv" Most commands will accept multiple switches after a single - unless they need a value supplied. As an example

"tcpdump -n -n -i eth0" can be shortened to "tcpdump -nni eth0"

If you need more than one switch to accept a value you can still consolidate except for the ones that need values.

"tcpdump -n -n -i eth0 -w capture.pcap" can be shortened to "tcpdump -nni eth0 -w capture.pcap"

-Otanx


TIL one more thing! Thanks, Otanx!

:tmyk:

[/me bumps Otanx' helpful rep]
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

deanwebb

#252
July 19, 2017, 03:49:01 PM
TIL that the "Open" in OSPF is not a verb, but an adjective, as in "open source".

http://www.tcpipguide.com/free/t_OSPFOverviewHistoryStandardsandVersions.htm

Also that the RFC for OSPFv2 is 240 pages long. Wow. Way to RFC, dudes!
Take a baseball bat and trash all the routers, shout out "IT'S A NETWORK PROBLEM NOW, SUCKERS!" and then peel out of the parking lot in your Ferrari.
"The world could perish if people only worked on things that were easy to handle." -- Vladimir Savchenko
Вопросы есть? Вопросов нет! | BCEB: Belkin Certified Expert Baffler | "Plan B is Plan A with an element of panic." -- John Clarke
Accounting is architecture, remember that!
Air gaps are high-latency Internet connections.

SofaKing

#253
July 21, 2017, 12:16:25 PM
TIL how to configure SSO on F5 APM for external users
Networking -  You can talk about us but you can't talk without us!

Otanx

#254
July 21, 2017, 01:41:36 PM
TIL that 6500 VSS is a bigger mess than I thought. Do you want to upgrade firmware? We have this cool ISSU/eFSU thing that will let you upgrade one chassis/sup card at a time. Oh, you want to upgrade from 15.1 to 15.2? You can't use ISSU. Need to reboot both at the same time.

Tomorrow I Learn (TIL) how to break a VSS with minimal down time.

-Otanx
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