2021-08-03 Emacs Wiki and IPv6

Here’s something weird: I can no longer connect to Emacs Wiki. At first, I thought it was only a problem on my iPhone or iPad, but apparently it’s more widespread.

Emacs Wiki

Could not connect to the server. NSURLErrorDomain

This is for Firefox and Safari which makes me think it’s a problem with the networking layer in the operating system, not the browser. I can connect just fine to the other domains hosted on the same machine (alike this one).

On my laptop, using traceroute:

alex@melanobombus ~> traceroute -n www.emacswiki.org
traceroute to www.emacswiki.org (178.209.50.237), 30 hops max, 60 byte packets
…
12  178.209.50.237  7.562 ms  7.605 ms  4.772 ms
alex@melanobombus ~> traceroute -n -4 emacswiki.org
traceroute to emacswiki.org (178.209.50.237), 30 hops max, 60 byte packets
…
12  178.209.50.237  2.809 ms  5.176 ms  5.716 ms
alex@melanobombus ~> traceroute -n -6 www.emacswiki.org
www.emacswiki.org: Name or service not known
Cannot handle "host" cmdline arg `www.emacswiki.org' on position 1 (argc 3)
alex@melanobombus ~> traceroute -n -6 emacswiki.org
traceroute to emacswiki.org (2a02:418:6a04:178:209:50:237:1), 30 hops max, 80 byte packets
…
12  2a02:418:6a04:178:209:50:237:1  8.651 ms  9.542 ms  7.917 ms

Apparently, there’s an IPv6 problem for www.emacswiki.org but not for emacswiki.org?

Checking DNS…

@ 10800 IN SOA ns1.gandi.net. hostmaster.gandi.net. 1589061328 10800 3600 604800 10800
@ 10800 IN A 178.209.50.237
@ 10800 IN AAAA 2a02:418:6a04:178:209:50:237:1
@ 10800 IN MX 10 aspmx1.migadu.com.
@ 10800 IN MX 20 aspmx2.migadu.com.
@ 10800 IN TXT "openpgp4fpr:df9446eb7b7846387ccc018bc78ca29bacecfeae"
@ 10800 IN TXT "v=spf1 a mx include:spf.migadu.com ~all"
_dmarc 10800 IN TXT "v=DMARC1; p=reject"
default._domainkey 10800 IN TXT "v=DKIM1; k=rsa; s=email; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCmaqj01Yu19QPNpkSbuQJNZ8OIe4h3gYw3WPqdDxC0OIN5HMxlNFE3AWcpgdmjgjBF2a3X63Ux8PExP6f0qPBoiMO0wvV3MhSwF1kXwuzuhTgtlwf+3v7EIGytQJ8+Y88+bgRfRhaRQfkTeEw1EI2/5yLeEWpqZOdV3tYyvx8dawIDAQAB"
www 10800 IN A 178.209.50.237

That’s right: no AAAA record for www!

For the moment, dig is reporting it’s OK:

alex@melanobombus ~> dig -t AAAA www.emacswiki.org

; <<>> DiG 9.11.5-P4-5.1+deb10u5-PureOS <<>> -t AAAA www.emacswiki.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12984
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.emacswiki.org.		IN	AAAA

;; ANSWER SECTION:
www.emacswiki.org.	10800	IN	AAAA	2a02:418:6a04:178:209:50:237:1

;; Query time: 24 msec
;; SERVER: …
;; WHEN: Tue Aug 03 07:40:42 CEST 2021
;; MSG SIZE  rcvd: 74

alex@melanobombus ~> dig -6 -t AAAA www.emacswiki.org

; <<>> DiG 9.11.5-P4-5.1+deb10u5-PureOS <<>> -6 -t AAAA www.emacswiki.org
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 7984
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;www.emacswiki.org.		IN	AAAA

;; ANSWER SECTION:
www.emacswiki.org.	10631	IN	AAAA	2a02:418:6a04:178:209:50:237:1

;; Query time: 4 msec
;; SERVER: …
;; WHEN: Tue Aug 03 07:43:31 CEST 2021
;; MSG SIZE  rcvd: 74

Well, that alone does not fix it. How strange.

alex@melanobombus ~> traceroute -n -6 www.emacswiki.org
www.emacswiki.org: Name or service not known
Cannot handle "host" cmdline arg `www.emacswiki.org' on position 1 (argc 3)

Firefox also seems to be caching the info somewhere. I always suspect that it has its own DNS subsystem somewhere. In any case, setting “network.dnsCacheExpiration” and “network.dnsCacheExpirationGracePeriod” both to 0 and then back to 60 did not help.

But yeah, something is still amiss. It’s not just Firefox – curl is doing it, too:

alex@melanobombus ~> curl -I https://emacswiki.org
HTTP/1.1 301 Moved Permanently
Date: Tue, 03 Aug 2021 05:36:31 GMT
Server: Apache
Permissions-Policy: interest-cohort=()
Location: https://www.emacswiki.org/
Content-Type: text/html; charset=iso-8859-1

alex@melanobombus ~> curl -I https://www.emacswiki.org
curl: (7) Failed to connect to www.emacswiki.org port 443: Connection refused

​#Emacs ​#Administration

Comments

(Please contact me if you want to remove your comment.)

Looks like we’re back! I wonder why this happened. Did somebody switch on IPv6 and no other Emacs Wiki user ever used IPv6?

– Alex 2021-08-03 06:55 UTC

---

Firefox might be using DoH (DNS over HTTP) with a default server at CloudFlare. You can either force it back to using normal DNS, or (like I finally did) run your own DoH service because that’s the new hipster, secure thing to do or some $​#!? like that.

– Sean Conner 2021-08-04 02:11 UTC

Sean Conner