Date: Tue, 05 Jan 2021 20:46:57 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 252449] telnet(1) regression or incompatibility in recent 12.2-STABLE Message-ID: <bug-252449-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=252449 Bug ID: 252449 Summary: telnet(1) regression or incompatibility in recent 12.2-STABLE Product: Base System Version: 12.2-STABLE Hardware: arm64 OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: zarychtam@plan-b.pwste.edu.pl Created attachment 221307 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=221307&action=edit Traffic dumps I have recently upgraded a few systems running 12.2-STABLE and after upgrading one by one I am losing the ability to connect with some Alcatel-Lucent switches (Omniswitch 63xx and 64xx models). Connection with the host seems to be established, but I am not able to get the login prompt: telnet 172.x.x.x Trying 172.x.x.x... Connected to 172.x.x.x. Escape character is '^]'. ^] This state last forever and the session can be only terminated. Telneting to other devices, from other vendors or even some different ALU switches, still goes fine. Since I was upgrading systems one by one and losing connectivity, I took some tcpdumps to document this oddity. Perhaps the culprit is TCP stack or its settings, which are the same on all machines: net.inet.tcp.ecn.enable=1 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1448 net.inet.tcp.syncache.rexmtlimit=1 net.inet.tcp.drop_synfin=1 net.inet.tcp.rfc6675_pipe=1 net.inet.tcp.abc_l_var=44 net.inet.tcp.functions_default=rack net.inet.tcp.cc.algorithm=htcp net.inet.tcp.cc.htcp.rtt_scaling=1 net.inet.tcp.cc.htcp.adaptive_backoff=1 net.inet.tcp.fastopen.server_enable=1 When the system is booted from kernel.old telnet from new userland and above TCP stack settings is able to connect again. -- You are receiving this mail because: You are the assignee for the bug.help
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