Invalidity dossier
US 5777989
TCP/IP host name resolution for machines on several domains
Current assignee: International Business Machines Corp
Added 9/21/2026, 10:20:58 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,777,989
Title: TCP/IP host name resolution for machines on several domains
Assignee: International Business Machines Corp. (IBM), original assignee; inventor John Ryan McGarvey.
Dates: Priority/filing date 1995-12-19; publication/grant 1998-07-07; anticipated expiration 2015-12-19. Status listed as "Expired – Lifetime" (a legal-status assumption, not a legal conclusion).
Purpose: TCP/IP name resolution conventionally assumes a host connects to a single domain whose name servers can resolve all hosts on the network — an assumption stated in RFC 1034, section 2.4. That assumption fails when a host is simultaneously connected to multiple domains (e.g., a private network and the Internet), because each domain's name servers cannot resolve names in the other. The invention remedies this by enhancing TCP/IP address resolution so a host attached to several domains can resolve destination addresses across them.
Plain-language scope: The local host is configured with two or more primary domain name servers, one per connected domain, with server names kept in lists (primary first, alternates following). Resolution requests are sent simultaneously to the primary servers in all domains; if any queried server returns a positive response, the corresponding address is used. The enhancement preserves standard name resolution processing (short names concatenated with configured domain names into fully qualified names), leaves the name resolution packet format unchanged, works with existing networks and servers, and supports existing RFC 1034 query types (name-to-address, address-to-name, MX/mail resolution). Queries may be carried via TCP virtual circuits, UDP datagrams, or other packets.
What the excerpt does not establish: It does not provide the full claims, complete description, or drawing contents; details of omitted text; any prosecution history; validity, enforceability, or infringement analysis; litigation; ownership transfers beyond the recorded IBM assignment; or prior-art comparisons. No such matters are asserted here.
Generated 10/1/2026, 10:01:46 PM
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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