IPv6 day stats – Tony Finch

Here are some numbers from yesterday's activity on the University of Cambridge's central mail relays. We advertised AAAA records for our services between about 08:20 and 20:30 local time (+01:00). We did not make any changes to the A records which point at IPv4-only servers; the added AAAA records pointed at a couple of dual-stack servers.

Incoming mail: mx.cam.ac.uk

223651 messages over IPv4
2204 messages over IPv6
1.0% ipv6

A lot of nerdy senders. Prominent on the list were NANOG, the IETF, FreeBSD, Debian, Haskell, UKNOF, Exim, Lua, ISC, Tor. The stats are somewhat distorted by my own personal mailing list subscriptions! Apart from that we got mail over IPv6 from several universities: Imperial, Vienna, Reading, TU-Berlin, Southampton (ECS), Valencia, Leicester, Oslo, Malta. Notable service providers include Retrosnub, chiark, Mythic Beasts, Fastmail, Andrews & Arnold, Bytemark.

Outgoing smart host: ppsw.cam.ac.uk

122384 messages over IPv4
3915 messages over IPv6
3.1% IPv6

This traffic reflects which parts of the University have IPv6 connectivity. Almost all came from the SRCF (which handles a lot of mail) and the Institute of Astronomy.

Message submission service: smtp.hermes.cam.ac.uk

90015 messages over IPv4
226 messages over IPv6
of which 185 were over 6to4
and 6 from outside the University
0.25% IPv6
0.20% 6to4

Again almost all this traffic is internal to the University so it reflects the proportion of IPv6 connectivity on our edge networks. A lot of these have poor layer 2 security, in particular little protection against rogue router advertisements.

Outgoing mail from the dual-stack servers

6103 outgoing deliveries total
5907 over IPv4
196 over IPv6
3.2% IPv6
1759 to internal University destinations
117 over IPv6
6.7% IPv6
4344 messages delivered to external destinations
79 over IPv6
1.8% IPv6

All this mail arrived over IPv6. You can see the effect of the SRCF and Astronomy again.

Mail reader access webmail/imap/pop.hermes.cam.ac.uk

The rightmost columns below are v6 logins from outside the University.

		v4	v6	%	6to4	%	ext	%
webmail	logins	72149	525	0.7%	194	37%	141	27%
	clients	15696	135	0.9%	83	61%	18	13%
imaps	logins	361956	752	0.2%	407	54%	144	19%
	clients	10380	101	1.0%	56	55%	20	20%
imap-tls	logins	117109	295	0.25%	27	9%	76	26%
	clients	4312	41	0.9%	10	24%	10	24%
pops	logins	162738	128	0.1%	41	32%	55	43%
	clients	2629	6	0.2%	4	67%	1	17%
pop-tls	logins	27741	0
	clients	453	0