Pi3 answers ssh only if outbound ping is running on -current
Date: Sat, 12 Feb 2022 18:56:18 UTC
For a few weeks now a Pi3 running -current will not respond to an incoming ssh connection unless an outbound ping process is running. Once the outbound ping is started via the serial console, incoming ssh connections are answered normally. Uname -a reports FreeBSD www.zefox.org 14.0-CURRENT FreeBSD 14.0-CURRENT #10 main-n253073-6db44b0158c: Sat Feb 12 04:30:21 PST 2022 bob@www.zefox.org:/usr/obj/usr/src/arm64.aarch64/sys/GENERIC arm64 A Pi4 running -current of a few days ago exhibits no such problems. Another Pi3 running stable/13 has been behaving in the same way. Both Pi3s successfully set time via ntp on reboot and will very briefly (one or two minutes) prompt for an ssh password, but no further progress is made and the login attempt times out. If the ssh login is attempted a second time, not even a password prompt comes back. Ping times (to an adjacent machine on the same subnet are 64 bytes from 50.1.20.26: icmp_seq=2 ttl=64 time=0.978 ms 64 bytes from 50.1.20.26: icmp_seq=3 ttl=64 time=0.967 ms 64 bytes from 50.1.20.26: icmp_seq=4 ttl=64 time=1.088 ms 64 bytes from 50.1.20.26: icmp_seq=5 ttl=64 time=0.983 ms 64 bytes from 50.1.20.26: icmp_seq=6 ttl=64 time=1.007 ms 64 bytes from 50.1.20.26: icmp_seq=7 ttl=64 time=1.075 ms 64 bytes from 50.1.20.26: icmp_seq=8 ttl=64 time=1.020 ms 64 bytes from 50.1.20.26: icmp_seq=9 ttl=64 time=1.044 ms 64 bytes from 50.1.20.26: icmp_seq=10 ttl=64 time=1.026 ms 64 bytes from 50.1.20.26: icmp_seq=11 ttl=64 time=0.908 ms That might be considered slow, but the correspondent machine is only a Pi2 running FreeBSD www.zefox.com 14.0-CURRENT FreeBSD 14.0-CURRENT #3 main-71d2d5adfe: Tue Dec 21 00:23:51 PST 2021 bob@www.zefox.com:/usr/obj/usr/freebsd-src/arm.armv7/sys/GENERIC arm If the outbound ping is started, an incoming ssh connection established and the outbound ping subsequently stopped the running ssh connection silently freezes; no disconnect, but no response, not even echo. Some tens of seconds later, all inputs were responded to. Tried a second time, the stoppage recurred, restarting the outbound ping eventually restored responsiveness. With the outbound ping stopped, an inbound ssh attempt silently failed: bob@raspberrypi:~ $ ssh -vvv 50.1.20.28 OpenSSH_7.9p1 Raspbian-10+deb10u2+rpt1, OpenSSL 1.1.1d 10 Sep 2019 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 19: Applying options for * debug2: resolve_canonicalize: hostname 50.1.20.28 is address debug2: ssh_connect_direct debug1: Connecting to 50.1.20.28 [50.1.20.28] port 22. [enter key echoed] debug1: connect to address 50.1.20.28 port 22: Connection timed out ssh: connect to host 50.1.20.28 port 22: Connection timed out bob@raspberrypi:~ $ Thanks for reading and any insights. If I've omitted useful details or tests please indicate. bob prohaska