| 1 | .\" @(#)mailaddr.7 4.2 %G% |
| 2 | .TH MAILADDR 7 |
| 3 | .UC 4 |
| 4 | .SH NAME |
| 5 | mailaddr \- mail addressing description |
| 6 | .SH DESCRIPTION |
| 7 | Mail addresses are based on the ARPANET protocol |
| 8 | listed at the end of this manual page. |
| 9 | These addresses are in the general format |
| 10 | .PP |
| 11 | user@domain |
| 12 | .PP |
| 13 | where a domain is a hierarchical dot separated list of subdomains. |
| 14 | For example, |
| 15 | the address |
| 16 | .PP |
| 17 | eric@monet.Berkeley.ARPA |
| 18 | .PP |
| 19 | is normally interpreted from right to left: |
| 20 | the message should go to the ARPA name tables |
| 21 | (which do not correspond exactly to the physical ARPANET), |
| 22 | then to the Berkeley gateway, |
| 23 | after which it should go to the local host monet. |
| 24 | When the message reaches monet it is delivered to the user ``eric''. |
| 25 | .PP |
| 26 | Unlike some other forms of addressing, |
| 27 | this does not imply any routing. |
| 28 | Thus, |
| 29 | although this address is specified as an ARPA address, |
| 30 | it might travel by an alternate route |
| 31 | if that was more convenient or efficient. |
| 32 | For example, |
| 33 | at Berkeley the associated message |
| 34 | would probably go directly to monet over the Ethernet |
| 35 | rather than going via the Berkeley ARPANET gateway. |
| 36 | .PP |
| 37 | .I Abbreviation. |
| 38 | Under certain circumstances |
| 39 | it may not be necessary to type the entire domain name. |
| 40 | In general anything following the first dot |
| 41 | may be omitted |
| 42 | if it is the same as the domain from which you are sending the message. |
| 43 | For example, |
| 44 | a user on |
| 45 | ``calder.Berkeley.ARPA'' |
| 46 | could send to |
| 47 | ``eric@monet'' |
| 48 | without adding the |
| 49 | ``.Berkeley.ARPA'' |
| 50 | since it is the same on both sending and receiving hosts. |
| 51 | .PP |
| 52 | Certain other abbreviations may be permitted |
| 53 | as special cases. |
| 54 | For example, |
| 55 | at Berkeley ARPANET hosts can be referenced |
| 56 | without adding the |
| 57 | ``.ARPA'' |
| 58 | as long as their names do not conflict |
| 59 | with a local host name. |
| 60 | .PP |
| 61 | .I Compatibility. |
| 62 | Certain old address formats |
| 63 | are converted to the new format |
| 64 | to provide compatibility with the previous mail system. |
| 65 | In particular, |
| 66 | .PP |
| 67 | host:user |
| 68 | .PP |
| 69 | is converted to |
| 70 | .PP |
| 71 | user@host |
| 72 | .PP |
| 73 | to be consistent with the |
| 74 | .IR rcp (1C) |
| 75 | command. |
| 76 | .PP |
| 77 | Also, the syntax: |
| 78 | .PP |
| 79 | host!user |
| 80 | .PP |
| 81 | is converted to: |
| 82 | .PP |
| 83 | user@host.UUCP |
| 84 | .PP |
| 85 | This is normally converted back to the |
| 86 | ``host!user'' |
| 87 | form |
| 88 | before being sent on for compatibility with older UUCP hosts. |
| 89 | .PP |
| 90 | The current implementation is not able to route messages |
| 91 | automatically through the UUCP network. |
| 92 | Until that time you must explicitly tell the mail system |
| 93 | which hosts to send your message through |
| 94 | to get to your final destination. |
| 95 | .PP |
| 96 | .I Case Distinctions. |
| 97 | Domain names (i.e., anything after the ``@'' sign) |
| 98 | may be given in any mixture of upper and lower case |
| 99 | with the exception of UUCP hostnames. |
| 100 | Most hosts accept any mixture of case in user names, |
| 101 | with the notable exception of MULTICS sites. |
| 102 | .PP |
| 103 | .I Differences with ARPA Protocols. |
| 104 | Although the UNIX addressing scheme |
| 105 | is based on the ARPA mail addressing protocols, |
| 106 | there are some significant differences. |
| 107 | .PP |
| 108 | At the time of this writing |
| 109 | the only |
| 110 | ``top level'' |
| 111 | domain defined by ARPA is the |
| 112 | ``.ARPA'' |
| 113 | domain itself. |
| 114 | This is further restricted to having only one level of host specifier. |
| 115 | That is, |
| 116 | the only addresses that ARPA accepts at this time must be in the format |
| 117 | ``user@host.ARPA'' |
| 118 | (where ``host'' is one word). |
| 119 | In particular, |
| 120 | addresses such as: |
| 121 | .PP |
| 122 | eric@monet.Berkeley.ARPA |
| 123 | .PP |
| 124 | are not currently legal |
| 125 | under the ARPA protocols. |
| 126 | For this reason, |
| 127 | these addresses are converted to a different format on output |
| 128 | to the ARPANET, |
| 129 | typically: |
| 130 | .PP |
| 131 | eric%monet@Berkeley.ARPA |
| 132 | .PP |
| 133 | .I Route-addrs. |
| 134 | Under some circumstances |
| 135 | it may be necessary to route a message |
| 136 | through several hosts |
| 137 | to get it to the final destination. |
| 138 | Normally this routing is done automatically, |
| 139 | but sometimes it is desirable to route the message manually. |
| 140 | An address that shows these relays are termed |
| 141 | ``route-addrs.'' |
| 142 | These use the syntax: |
| 143 | .PP |
| 144 | <@hosta,@hostb:user@hostc> |
| 145 | .PP |
| 146 | This specifies that the message should be sent to hosta, |
| 147 | from there to hostb, |
| 148 | and finally to hostc. |
| 149 | This path is forced |
| 150 | even if there is a more efficient path |
| 151 | to hostc. |
| 152 | .PP |
| 153 | Route-addrs |
| 154 | occur frequently on return addresses, |
| 155 | since these are generally augmented by the software |
| 156 | at each host. |
| 157 | It is generally possible to ignore all but the |
| 158 | ``user@host'' |
| 159 | part of the address to determine the actual sender. |
| 160 | .PP |
| 161 | .I Postmaster. |
| 162 | Every site is required to have a user or user alias |
| 163 | designated |
| 164 | ``postmaster'' |
| 165 | to which problems with the mail system may be addressed. |
| 166 | .PP |
| 167 | .I CSNET. |
| 168 | Messages to CSNET sites can be sent to |
| 169 | ``user.host@UDel-Relay''. |
| 170 | .SH BERKELEY |
| 171 | The following comments apply only to the Berkeley environment. |
| 172 | .PP |
| 173 | .I Host Names. |
| 174 | Many of the old familiar host names |
| 175 | are being phased out. |
| 176 | In particular, |
| 177 | single character names as used in Berknet |
| 178 | are incompatible with the larger world |
| 179 | of which Berkeley is now a member. |
| 180 | For this reason |
| 181 | the following names |
| 182 | are being obsoleted. |
| 183 | You should notify any correspondents |
| 184 | of your new address |
| 185 | as soon as possible. |
| 186 | .PP |
| 187 | .ta 1i 1.2i 2.5i |
| 188 | OLD NEW |
| 189 | j ingvax ucbingres |
| 190 | p ucbcad |
| 191 | r arpavax ucbarpa |
| 192 | v csvax ucbernie |
| 193 | n ucbkim |
| 194 | y ucbcory |
| 195 | .PP |
| 196 | The old addresses will be rejected as unknown hosts |
| 197 | sometime in the near future. |
| 198 | .PP |
| 199 | .I What's My Address? |
| 200 | If you are on a local machine, |
| 201 | say monet, |
| 202 | your address is |
| 203 | .PP |
| 204 | yourname@monet.Berkeley.ARPA |
| 205 | .PP |
| 206 | However, since most of the world does not have the new software |
| 207 | in place yet, |
| 208 | you will have to give correspondents slightly different addresses. |
| 209 | From the ARPANET, |
| 210 | your address would be: |
| 211 | .PP |
| 212 | yourname%monet@Berkeley.ARPA |
| 213 | .PP |
| 214 | From UUCP, your address would be: |
| 215 | .PP |
| 216 | ucbvax!yourname%monet |
| 217 | .PP |
| 218 | .I Computer Center. |
| 219 | The Berkeley Computer Center |
| 220 | is in a subdomain of Berkeley. |
| 221 | Messages to the computer center |
| 222 | should be addressed to: |
| 223 | .PP |
| 224 | user%host.CC@Berkeley.ARPA |
| 225 | .PP |
| 226 | The alternate syntax: |
| 227 | .PP |
| 228 | user@host.CC |
| 229 | .PP |
| 230 | may be used if the message is sent from inside Berkeley. |
| 231 | .PP |
| 232 | For the time being |
| 233 | Computer Center hosts |
| 234 | are known within the Berkeley domain, |
| 235 | i.e., |
| 236 | the |
| 237 | ``.CC'' |
| 238 | is optional. |
| 239 | However, |
| 240 | it is likely that this situation will change |
| 241 | with time as both the Computer Science department |
| 242 | and the Computer Center grow. |
| 243 | .PP |
| 244 | .I Bitnet. |
| 245 | Hosts on bitnet may be accessed using: |
| 246 | .PP |
| 247 | user@host.BITNET |
| 248 | .PP |
| 249 | .SH BUGS |
| 250 | The RFC822 group syntax |
| 251 | (``group:user1,user2,user3;'') |
| 252 | is not supported except in the special case of |
| 253 | ``group:;'' |
| 254 | because of a conflict with old berknet-style addresses. |
| 255 | .SH SEE ALSO |
| 256 | mail(1), sendmail(8); |
| 257 | Crocker, D. H., |
| 258 | .ul |
| 259 | Standard for the Format of Arpa Internet Text Messages, |
| 260 | RFC822. |