Cisco Bug: CSCsz47656 - telnetd shall age out the zombie "half-open" session
May 16, 2018
- Cisco Carrier Routing System
Known Affected Releases
Symptom: Telnet access not working anymore and telnetd processes blocked on tcp : sh proc block Jid Pid Tid Name State Blocked-on ... 65723 16093371 1 telnetd Reply 221354 tcp 65729 16093377 1 telnetd Reply 221354 tcp 65763 16081123 1 telnetd Reply 221354 tcp 65764 16101604 1 telnetd Reply 221354 tcp Conditions: When a tcp connexion is open to port 23 but the remote client doesn't do telnet option negotiation, telnetd will keep waiting for telnet option (like terminal type) as far as the tcp connexion is not closed by the remote end. This comes before the user authentication phase so doesn't consume a VTY line but will limit the number of concurrent telnet connexions.
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Bug Details Include
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