September 2025 - NANOG - lists.nanog.org

LAG/ECMP and 'exact-route'
by Saku Ytti 23 Jun '26

23 Jun '26

Hey-o, Which platform/software has a command to show which interface will be used for forwarding with given keys? ASR9k has a cef exec-route, and I see references to this in c-nsp, reddit and cisco.com forums, stressing how useful debugging tool it has been. Despite it not actually working, since it's just RE software, it doesn't talk to the EZchip/lightspeed, unless it has been fixed in the past couple of years, certainly hasn't worked in the timeline of various forums finding it useful. MX has 'jsim' https://www.juniper.net/documentation/en_US/day-one-books/TW_MX3D_PacketWal… which I think actually works, but it is quite involved. I have some (false?) memory that I saw in some release note this being a bit more productised into CLI command, but I'm failing to find anything to support this memory. There is also RFC5837, which is actually implemented in QFX5k, but not for TTL exceeded, we've opened ER to get it supported on MX and PTX and for TTL exceeded. This RFC will allow programmatic platform agnostic discovery of the actual interface used, without relying on platform specific magic. So please do ask your vendors to implement it. -- ++ytti

7 11

is it just me or...
by Michael Thomas 14 Apr '26

14 Apr '26

I'm using Thunderbird to read mail and lately the only thing I've seen in the mail.from address is |North American Network Operators Group | and not the author's address which makes it really hard to tell who is talking to whom. I is just me, or has there been a list config change that is causing this? Mike

29 83

Correctly dealing with bots and scrapers.
by Andrew Latham 25 Mar '26

25 Mar '26

I just had an issue with a web-server where I had to block a /18 of a large scraper. I have some topics I could use some input on. 1. What tools or setups have people found most successful for dealing with bots/scrapers that do not respect robots.txt for example? 2. What tools for response rate limiting deal with bots/scrapers that cycle over a large variety of IPs with the exact same user agent? 3. Has anyone written or found a tool to concentrate IP addresses into networks for IPTABLES or NFT? (60% of IPs for network X in list so add network X and remove individual IP entries.) -- - Andrew "lathama" Latham -

18 33

New c-nsp, j-nsp, a-nsp, etc mailing lists
by Drew Weaver 20 Jan '26

20 Jan '26

I was a big fan of the *-nsp(a)puck.nether.net<mailto:*-nsp@puck.nether.net> mailing lists that now seem to be completely gone without any indication of whether or when they might return. I've been considering just setting up new ones. Please email me off-list if you think this might be useful. Thanks, -Drew

15 25

Hardware question
by Craig Smith 10 Nov '25

10 Nov '25

Hello, Is anyone out there aware of a fail safe switch/router/1U server where upon power failure or watchdog event 2 ports would fail to pass through data, but could also be assigned an IP address and act as a bridge in "normal" mode? The desire is to have an appliance that could perform monitoring and send telemetry in between a customer device and an Internet connection but not create a single point of failure or require multiple ISP handoffs. Best, Craig

14 18

IP Address support in spreadsheets?
by Bryan Fields 20 Oct '25

20 Oct '25

Has anyone found a solution to represent IPv4 addresses in a spreadsheet, preferably Google Sheets? I'm not here to debate the use of spreadsheets for tracking IP addresses, just find something better than storing v4 dotted decimal as text in a spreadsheet. We don't need v6 at this time; we're using a spreadsheet for tracking addressing, v6 is beyond us. At minimum we need to store it as a 32 bit INT, and display as dotted decimal. If there's some way to make it aware of subnet slash notation, so much the better. I'm a bit at a loss as to why there's no IPv4 number format with how often spreadsheets are the source of truth in some rather large service providers. Again, not looking for non-spreadsheet solutions to this, and ideally a web interface spreadsheet would be best for sharing. We don't need a real database if it's on the web :-) -- Bryan Fields 727-409-1194 - Voice http://bryanfields.net

13 16

Best recommendation for out of band router access?
by Jonathan Kalbfeld 03 Oct '25

03 Oct '25

Hello, Obviously dial up is no longer practical for most applications. I have a some of my gear co-located in a facility in downtown Los Angeles where the idea of paying a monthly for a cross connect to get a phone line is just not practical. Can anyone recommend an idea that's not super cost prohibitive that would involve some kind of 4G or 5G Sim with a static IP address that is not CGNAT? I'm running OpenBSD for my Edge routers, so plugging in a USB is not guaranteed, so is there a product that might have some kind of a bridge functionality where it will establish a mobile IP connection and then plug into my switch? Also open to reasonably priced provider recommendations. I don't need a lot of bandwidth since this would mostly just be SSH or maybe openvpn traffic. If you know of service providers as well as recommended products, that would be ideal. I don't want to spend thousands, but a few hundred dollars on gear seems reasonable. Very best, Jonathan Jonathan Kalbfeld office: +1 310 317 7933 fax: +1 310 317 7901 home: +1 310 317 7909 mobile: +1 310 227 1662 ThoughtWave Technologies, Inc. Studio City, CA 91604 https://thoughtwave.com View our network at https://bgp.he.net/AS54380 +1 844 42-LINUX

8 9

RFC8805 geofeed validation
by Yang Yu 01 Oct '25

01 Oct '25

Questions for folks ingesting geofeed, what do you use for address validation? Are non-ASCII characters supported, especially in City field? e.g. 부산 vs Busan What happens when Region field is empty? discard the line / use Country only / try to use Country + City (which may not be unique) Common parsing / validation errors? Thanks, Yang

4 3

NEC 2026 changes for data/communication wiring
by Sean Donelan 29 Sep '25

29 Sep '25

The 2026 National Electrical Code is ready for publication. The scope of Chapter 8 is changed from all building communication system installations, to only communications wiring outside or at the cable entrance point. Data/Communication system wiring is now in Chapter 7, which means it will be covered by general NEC requirements. For those designing data centers after 2026, many data/communication installation "best practices" will become code requirements. Probably the biggest change will "working clearances" for communications equipment in wiring closets and cabinet door openings in data centers. No more cramming equipment into shared closets or draping cables across the room. After the 2026 NEC is adopted, building code officials will be able to enforce those requirements.

4 7

ARIN 8.5.7
by Nicholas Warren 29 Sep '25

29 Sep '25

What is the purpose of 8.5.7? If the network must meet the requirements of 8.5.5 and 8.5.6, what is the use of 8.5.7 especially since it has a limit while 8.5.5 does not? "Each discrete network must meet the projection requirements in section 8.5.5 ... [and] must meet the utilization requirements in section 8.5.6" Nich Warren

1 0