What should be done if CorpDC3 cannot find the CorpWeb server?

If CorpDC3 is unable to locate the CorpWeb server, checking for synchronization issues in Active Directory is a vital step. Active Directory relies on synchronization to ensure that all domain controllers have the same directory data. If there are synchronization issues, it could result in CorpDC3 having outdated or missing information about the CorpWeb server, which is crucial for DNS resolution.

When servers that are part of a domain cannot communicate properly or do not have synchronized information, they may struggle to resolve hostnames to IP addresses correctly. Resolving synchronization issues means that CorpDC3 may obtain the correct data regarding CorpWeb's DNS records, allowing it to effectively locate the server.

While changing DNS settings for all servers, creating new records for CorpWeb, or restarting the DNS service may also seem like potential solutions, they do not directly address the root cause of the problem if the underlying issue is related to synchronization in Active Directory. Hence, confirming and resolving synchronization issues would be the most appropriate first action to take in this scenario.