HN meta: 99% packet loss on news.ycombinator.com

3 eqvinox 2 8/21/2025, 1:47:08 PM

I'm currently seeing >99% packet loss to news.ycombinator.com (2606:7100:1:67::26):

  13. br06-te1-2.lwdc.americanis.net                   0.0%   231   14.3  17.2  14.0 172.5  19.5
  14. sdtc.sd-me01.te0-1.host1.20546.americanis.net   99.6%   231   12.9  12.9  12.9  12.9   0.0
  15. 2606:7100:1:67::26                              99.1%   231   11.8  11.8  11.8  11.8   0.0

Checked from both US and EU connections, same result, would be a very odd coincidence if it was a problem on my end. Trace looks like the uplink provider is having issues?

IPv4 seems to be unaffected.

Comments (2)

Bender · 15m ago

Packet loss over ICMP can be artificial based on the backplane load of routers, ACL's and artificial rate limits. They will de-prioritize responding to ICMP and fail to respond if CPU load is high but that does not mean the packets are not being forwarded 100%. Linux and BSD also have knobs for this behavior as well. HN is BSD.

Are you seeing TCP retransmits to port 443?

    for i in $(seq 69);do nc -vz -w1 news.ycombinator.com 443;sleep 2;done

Do that at the same time as watching

    watch -d -n4 --no-title 'nstat -a|grep -Ei "ret|los"'

It would be most useful to do this from your location and also from VM's on a few different providers in different locations to find which thing is not like the other. The 'nc' I am using is part of the nmap distribution. To force IPv6 replace the name with the IPv6 address.

eqvinox · 3m ago

> Packet loss over ICMP can be artificial based on the backplane load of routers.

This doesn't generally apply to the end host; note the last hop in the trace I posted is the web server itself. Also, the second last hop having very similar loss% makes it likely that neither of the two systems is hitting rate limits (as they would be different).

> Are you seeing TCP retransmits to port 443?

If the webpage loaded normally, I wouldn't have investigated to begin with ;).

Right now, the loss on TCP SYNs is about 70%. (mtr -T -P 443) Second to last hop still has roughly the same loss. Something's h0rked at americanis.net.

Bender · 10s ago

[delayed]