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One oddball provider is NFS. The mount command can deal with domains simply tremendous, and you may placed domains into /etc/fstab (your seller may well name it /etc/checklist), too. yet beware of /etc/exports and /etc/netgroup. /etc/exports controls which filesystems you permit quite a few consumers to NFS-mount. you may also assign a reputation to a bunch of hosts in netgroup after which enable them entry through exports utilizing the identify of the gang. regrettably, older models of NFS do not fairly use DNS to examine exports or netgroup; the customer tells the NFS server its id in a distant technique name (RPC) packet. hence, the client's id is regardless of the buyer claims it really is, and the identification a number makes use of in sunlight RPC is the neighborhood host's hostname. So the identify you utilize in both dossier must fit the client's hostname, which is not inevitably its area identify. electronic message a few electronic message courses, together with sendmail, additionally do not paintings as anticipated; sendmail does not use the quest record relatively a similar means that different courses do. as an alternative, while configured to take advantage of a nameserver, it makes use of a procedure known as canonicalization to transform names in electronic message addresses to totally certified domains. In canonicalization, sendmail applies the hunt record to a reputation and appears up facts of sort ANY, which fits any form of list. sendmail makes use of an identical rule more recent resolvers do: if the identify to canonicalize has no less than one dot in it, payment the identify as-is first. If the nameserver queried unearths a CNAME checklist (an alias), sendmail replaces the identify appeared up with the canonical identify the alias issues to and canonicalizes that (in case the objective of the alias is itself an alias). If the nameserver queried unearths an A checklist (an address), sendmail makes use of the area identify that resolved to the deal with because the canonical identify. If the nameserver does not locate an tackle yet does locate a number of MX documents, one of many following activities is played: If the hunt record has no longer but been appended, sendmail makes use of the area identify that resolved to the MX record(s) because the canonical identify. If a number of parts of the quest record were appended, sendmail notes that the area identify is a possible canonical identify and maintains appending components of the quest checklist. If a next part of the quest checklist turns up an tackle, the area identify that became up the handle is the canonical identify. differently, the area identify that discovered the 1st MX list is used because the canonical identify. [*] sendmail makes use of canonicalization a number of occasions whilst processing an SMTP message; it canonicalizes the vacation spot deal with and a number of other fields within the SMTP headers. [†] sendmail additionally units macro $w to the canonicalized hostname while the sendmail daemon begins up. So no matter if you place your hostname to a quick, single-part identify, sendmail canonicalizes the hostname utilizing the hunt checklist outlined in resolv. conf. sendmail then provides macro $w and all aliases for $w encountered in the course of canonicalization to classification $=w, the checklist of the mail server's different names.