Re: Famous operational issues
On Fri, 19 Feb 2021, Andy Ringsmuth wrote: > > I explain using my "talking to a 5 year old" voice that it > > most certainly is a router. He tells me that lying to airport security > > is a federal offense, and starts looming at me. I adjust my attitude > > and start explaining that it's like a computer and makes the Internet > > work. He gruffly hands me back the router, I put it in my bag and > > scurry away. As I do so, I hear him telling his colleague that it > > wasn't a router, and that he certainly knows what a router is, because > > he does woodwork… > > Well, in his defense, he wasn’t wrong… :-) This is wjy, in the UK, we tend to pronounce "router" as "router", and "router" as "router", so there's no confusion. You're welcome. Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Multicast traffic % in enterprise network ?
In terms of other Internet use, the BBC recently published this white paper on the R&D efforts with HTTP Server Push/QUIC, part of which describes an "experimental IP multicast profile of HTTP over QUIC". https://www.bbc.co.uk/rd/publications/whitepaper336 Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263. On Thu, 9 Aug 2018, Curtis, Bruce wrote: > Multicast was also required for earlier versions of VXLAN. But later > versions or VXLAN only require unicast. > > For the far future it seems like Named Data Neworking, Content Centric > Networking, Information Centric Networking, Data Centric Networking etc all > list multicast as a requirement or fundamental part of their architecture. > > > On Aug 8, 2018, at 4:15 PM, Greg Shepherd wrote: > > > > Financial exchanges around the world use multicast. > > > > On Wed, Aug 8, 2018 at 1:31 PM, Stan Barber wrote: > > > >> As someone else remarked, part of this will depend on the type of network > >> you are profiling. One enterprise networking may have critical internal > >> applications that depend on multicast to work and others may have nothing > >> but the basic requirements of the network itself (e.g. IPv6 uses multicast > >> instead of broadcast for some network control information distribution). > >> > >> On Wed, Aug 8, 2018 at 11:49 AM, Mankamana Mishra (mankamis) via NANOG < > >> nanog@nanog.org> wrote: > >> > >>> Hi Every one, > >>> Recently we had good discussion over multicast uses in public internet. > >>> From discussion, it was pointed out uses of multicast is more with in > >>> enterprise. Wanted to understand how much % multicast traffic present in > >>> network > >>> > >>> * If there is any data which can provide what % of traffic is > >>> multicast traffic. And if multicast is removed, how much unicast traffic > >> it > >>> would add up? > >>> * Since this forum has people from deployment area, I would love to > >>> know if there is real deployment problems or its pain to deploy > >> multicast. > >>> > >>> > >>> These questions is to work / discussion in IETF to see what is pain > >> points > >>> for multicast, and how can we simplify it. > >>> > >>> > >>> > >>> Thanks > >>> Mankamana > >>> > >>> > >> > > > --- > Bruce Curtis bruce.cur...@ndsu.edu > Certified NetAnalyst II701-231-8527 > North Dakota State University > >
Re: The tale of a single MAC
On Sun, 2 Jan 2011, Steven Bellovin wrote: > > This was actually the intended way to use "MAC" addresses, to used as > > host addresses rather than as individual interface addresses, according > > to the following paper - > > > > "48-bit Absolute Internet and Ethernet Host Numbers" > > Yogan K. Dalal and Robert S. Printis, July 1981 > > http://ethernethistory.typepad.com/papers/HostNumbers.pdf > > Yup. > > > > That paper also discusses why 48 bits were chosen as the size, despite > > "Ethernet systems" being limited to 1024 hosts. > > > > I think things evolved into MAC per NIC because when add-in NICs > > were invented there wasn't any appropriate non-volatile storage on the > > host to store the address. > > > On really old Sun gear, the MAC address was stored on a separate ROM > chip; if the motherboard was replaced, you'd just move the ROM chip to > the new board. And I'm sure many will remember that Suns of a certain vintage with multiple ethernet interfaces would use that same "host" MAC address on all those interfaces, unless you weaved some magic in the eeprom to use the (presumably) burned-in MAC address of the interface itself. I have long forgotten precisely what the incantation was now ... Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: The tale of a single MAC
On Sun, 2 Jan 2011, Lynda wrote: > Google does NOT know all. I was there. I have had to deal with a > building full of such wickedness. I administered DNS (in my copious > spare time) for two subdomains, and managed the network in the building > (a not inconsiderable /22, and also in my spare time), and started > getting frantic calls from people who were getting knocked off the > network because their machine had the same MAC address as another. > > I had trouble believing it at first, but after dealing with five of them > (all Gateways, and yes, all with the same MAC address), I directed the > local sysadmins to disable the nic that came with them, and to replace > it with a spare. I understand that there were 30,000 of them, all with > the same address. My guess is that you'll never find it on Google, since > it happened around 1993-4 or so. You will now. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Is Cisco equpiment de facto for you?
On Mon, 10 Jan 2011, Greg Whynott wrote: > > Just as a pointer - one of the largest and most utilized IX (AMS-IX) > > has their platform built on Brocade devices. > > Brocade device's pre Foundry purchase correct? I can't see anyone that > large using Foundry in large deployments.. Probably not as large as AMX-IX, but London Internet Exchange (LINX): both as Foundry and Brocade. Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Understanding reverse DNS better
On Tue, 25 Jan 2011, Larry Smith wrote: > I use Squish (www.squish.net/dnscheck) for this purpose. Reasonable web > interface and gives lots of info about where things are breaking down... > > -- > Larry Smith squish.net/dnscheck is great, except when I've had problems with it, or wanted a second opinion. Does anyone know another site that offers much the same functionality? Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: ID10T out of office responders (was Re: Yahoo DMARC breakage)
On Fri, 11 Apr 2014, Tei wrote:
> Suppose I configure my email to send a "Thanks, we have received your
> email, we will reply shortly in office hours.". Whats the Holy Headers
> so even poorly configured servers don't cause a AutoReply Storm?
> Googling, I found "Precedence", "X-Auto-Response-Suppress",..? For
> something like this, normally I would scan lots of opensource projects
> in www.google.com/codesearch (so I can learn from the projects with
> a large number of hours in production) , but seems down at the
> moment.
If that's what you want to do, then setting one or more of these may help:
Auto-submitted: auto-generated
X-Auto-Response-Suppress: OOF
Precendence: bulk
(Other values of the last two are possible).
RFC3834 is background reading and references Auto-submitted:.
X-Auto-Response-Suppress: is used by MS Exchange/Outlook.
But if those servers really are "poorly configured", there's no guarantee
they will honour any of those anyway.
If you want more control for yourself, you need to filter the return
messages out. I do this in Exim to identify "automatically generated
email" to be thrown away in some circumstances:
condition = ${if or { \
{ match {$h_precedence:} {(?i)junk|bulk|list} } \
{ eq {$sender_address} {} } \
{ def:header_X-Cron-Env: } \
{ def:header_Auto-Submitted: } \
{ def:header_List-Id: } \
{ def:header_List-Help: } \
{ def:header_List-Unsubscribe: } \
{ def:header_List-Subscribe: } \
{ def:header_List-Owner: } \
{ def:header_List-Post: } \
{ def:header_List-Archive: } \
{ def:header_Autorespond: } \
{ def:header_X-Autoresponse: } \
{ def:header_X-Autoreply-From: } \
{ def:header_X-eBay-MailTracker: } \
{ def:header_X-MaxCode-Template: } \
{ match {$h_X-Auto-Response-Suppress: } {OOF} } \
{ match {$h_X-OS:} {HP Onboard Administrator} } \
{ match {$h_X-MimeOLE:} {\N^Produced By phpBB2$\N} } \
{ match {$h_Subject:} {\N^Yahoo! Auto Response$\N} } \
{ match {$h_Subject:} {\N^ezmlm warning$\N} } \
{ match {$h_X-FC-MachineGenerated:} {true} } \
{ match {$h_X-Spam-Flag:} {\N^yes\N} } \
{ match {$message_body} {\N^Your \"cron\" job on\N} } \
{ match {$h_Subject:} {\N^Out of Office\N} } \
{ match {$h_Subject:} {\N^Auto-Reply:\N} } \
{ match {$h_Subject:} {\N^Autoresponse:\N} } \
{ match {$h_Subject:} {\N(Auto Reply)$\N} } \
{ match {$h_Subject:} {\N(Out of Office)$\N} } \
{ match {$h_Subject:} {\Nis out of the office.$\N} } \
{ match {$h_From:} {\N(via the vacation program)\N } } \
{ ! match {$header_To: $header_CC: $header_Bcc: \
$header_Resent-To: $header_Resent-Cc: $header_Resent-Bcc:} \
} \
} {no} {yes} \
}
(I have not reviewed this for a very long time). Be careful.
Jethro.
. . . . . . . . . . . . . . . . . . . . . . . . .
Jethro R Binks, Network Manager,
Information Services Directorate, University Of Strathclyde, Glasgow, UK
The University of Strathclyde is a charitable body, registered in
Scotland, number SC015263.
Re: Writable SNMP
On Tue, 6 Dec 2011, Jeff Wheeler wrote: > On Tue, Dec 6, 2011 at 11:07 AM, Keegan Holley > wrote: > > For a few years now I been wondering why more networks do not use writable > > SNMP. Most automation solutions actually script a login to the various > ... > Juniper does not support writing via SNMP. I am glad. Hopefully that > is the first step toward not supporting SNMP at all. So what are the alternatives these days then for automation or batch operations? clogin etc from shrubbery's rancid? Net::Appliance::Session ... ? . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Hi speed trading - hi speed monitoring
On Thu, 16 Feb 2012, Hank Nussbacher wrote: > Nanosecond Trading Could Make Markets Go Haywire > http://www.wired.com/wiredscience/2012/02/high-speed-trading/ > > "Below the 950-millisecond level, where computerized trading occurs so > quickly that human traders can't even react, no fewer than 18,520 > crashes and spikes occurred." > > Anyone who has managed a network knows that when you look at your > MRTG/Cacti graphs at 5min, 10min ,15min intervals - all looks well. > Start looking at 1sec intervals and you will see spikes that hit 100% of > capacity - even on networks running at 25% average utilization. > > I guess trading and networking do have many unseen similarities. Tieing the two together, this post shows how a lot of 'conventional' network thinking needs to be turned on its head when it comes to networks for trading floors: http://www.fragmentationneeded.net/2011/12/pricing-and-trading-networks-down-is-up.html Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: DDI (DNS+DHCP+IPAM) Solutions
On Tue, 26 Jun 2012, Eric Cables wrote: > I'm looking to consolidate DNS/DHCP/IPAM into a single tool. Today I > use IPPlan for IPAM, and have been reasonably happy with it over the > last 5+ years, but I'd like to leverage the benefits of integrating DNS > and DHCP for real-time information, along with a more supportable > solution for my staff. It seems that InfoBlox and BlueCat are the top > players, but maybe I'm being fooled by the hype. You might like to add EfficientIP to your list to investigate. (I haven't bought any yet). Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: guys != gender neutral
On Thu, 27 Sep 2012, Landon Stewart wrote:
> On 27 September 2012 11:34, Owen DeLong wrote:
>
> > When did "people" stop being an acceptable gender-neutral substitute for
> > {guys,gals}?
> >
> > Owen
> >
> >
> Using the word 'people' is good but I like to say 'humans'.
>
> What's up humans?
> Can I get you humans to drink?
>
> This rarely offends anyone.
This discussion is a well-trodden (and tediously dull) path. My favourite
response to it:
http://list.uvm.edu/cgi-bin/wa?A2=ind1001&L=UVMRESNET&D=0&P=2278
Thank you Jason Healy.
Jethro.
. . . . . . . . . . . . . . . . . . . . . . . . .
Jethro R Binks, Network Manager,
Information Services Directorate, University Of Strathclyde, Glasgow, UK
The University of Strathclyde is a charitable body, registered in
Scotland, number SC015263.
RE: A case against vendor-locking optical modules
On Mon, 17 Nov 2014, Naslund, Steve wrote: > Let talk about the 800 pound gorilla in the room and the #1 reason to > hate vendor locked optics. Some vendors (yes, Cisco I'm looking at you) > want to charge ridiculously high prices for optic that are identical to > generic optics other than the vendor lock. Maybe a better tactic would > be to have the vendor explain to you why the vendor lock is necessary. > You are after all the customer and don't owe them any explanations. The Packetpushers recently discussed this issue: http://packetpushers.net/ps-show-35-oem-sfp-qsfp-modules-work/ Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Software Defined Networking
About every edition of Packet Pushers Podcast for the last 18 months would be a good start probably. That'll keep you busy. Jethro. On Fri, 4 Sep 2015, Rod Beck wrote: > Can anyone provide references on this top so I can educate myself? > > This e-mail and any attachments thereto is intended only for use by the > addressee(s) named herein and may be proprietary and/or legally privileged. > If you are not the intended recipient of this e-mail, you are hereby notified > that any dissemination, distribution or copying of this email, and any > attachments thereto, without the prior written permission of the sender is > strictly prohibited. If you receive this e-mail in error, please immediately > telephone or e-mail the sender and permanently delete the original copy and > any copy of this e-mail, and any printout thereof. All documents, contracts > or agreements referred or attached to this e-mail are SUBJECT TO CONTRACT. > The contents of an attachment to this e-mail may contain software viruses > that could damage your own computer system. While Hibernia Networks has taken > every reasonable precaution to minimize this risk, we cannot accept liability > for any damage that you sustain as a result of software viruses. You should > carry out your own virus checks before opening any attachment. > . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: iOS 7 update traffic
On Thu, 19 Sep 2013, Cutler James R wrote: > --As a side note, IOS 7 fixes/improves iDevices in multiple areas, > making it a compelling upgrade. That's supposed to be the nature of upgrades. If that's where the matter ended then you'd have no argument. The problem is when it comes to the new bugs that get introduced, and whether they affect features you care about. I'm holding back until next week :) (And after previous bitter experience with over-the-air upgrade, I've downloaded it through iTunes to a desktop and will upgrade it by wire at my leisure). Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Network Manager, Information Services Directorate, University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
Re: Real ops talking to future ops
On Mon, 23 Aug 2010, John Kristoff wrote: > On Mon, 23 Aug 2010 20:17:53 -0400 > ML wrote: > > > I'm just as surprised as you are. They left out AppleTalk. > > A few classes ago I had a student tell me they had an instructor spend > two full classes (out of 10) on Token Ring. I think Token Ring is > interesting and I feel a little bit sad about all the token ring > experience I have that is slowly rotting to history with no one to pass > it on to, but was a wow for me at the time. Maybe there's hope for you yet: http://fcotr.org/ Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks, Computing Officer Information Services, The University Of Strathclyde, Glasgow, UK The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.
RE: 10GBase-t switch
On Thu, 11 Mar 2010, Greg Whynott wrote: > Brocade is the king of license gouging, it is no surprise they want > money to view a pdf. To be fair, Foundry removed their manuals from public view a good few years ago, long before Brocade came on the scene. It annoyed me too. Jethro. . . . . . . . . . . . . . . . . . . . . . . . . . Jethro R Binks Computing Officer, IT Services, University Of Strathclyde, Glasgow, UK > > From: David Hubbard [dhubb...@dino.hostasaurus.com] > Sent: Thursday, March 11, 2010 1:31 PM > To: nanog@nanog.org > Subject: RE: 10GBase-t switch > > From: Malte von dem Hagen [mailto:m...@hosteurope.de] > > > > Hi, > > > > Am 11.03.10 16:29 schrieb Dylan Ebner: > > > Do the Arista switches support netflow? > > > > nothing about it in the datasheets, and regarding documentation: > > > > "A registered account and a valid support contract is required to > > access the Software Download and Documentation section of the > > website." > > > > Service fail. > > +1 > > After Brocade started doing that with the Foundry > docs, which hung me out to dry one night when I > needed some docs I didn't have easy access to, I > decided I will try to avoid buying from companies > that require a support contract to read the manual. > > David > > >
