dwig@b11.ingr.com (David Wiggins) (07/19/90)
We have a problem making X connections to hosts whose names are pure
numbers, e.g. 2020. MakeTCPConnection (XConnDis.c) tries to use this
as an IP address instead of a host name. This appears to succeed
(inet_addr does not return INVALID_INETADDR), but the connect fails
because there's no machine with that address on the network.
What we'd like to do is change Xlib to interpret the hostname string as
a hostname first (via gethostbyname), and if there's no such host,
interpret it as an IP address (via inet_addr), effectively reversing the
order that Xlib currently uses. Would this introduce any new problems?
I balk at changing the order because the following comment...
/*
* if numeric host name then try to parse it as such; do the number
* first because some systems return garbage instead of INVALID_INETADDR
*/
...indicates that there was a good reason for the current order. Anybody
understand what this comment means?
David P. Wiggins dwig@ingr.com or uunet!ingr!dwig (205)730-6365
Intergraph Corporation, One Madison Industrial Park, Huntsville, AL 35807casey@gauss.llnl.gov (Casey Leedom) (07/27/90)
| From: dwig@b11.ingr.com (David Wiggins) | | We have a problem making X connections to hosts whose names are pure | numbers, e.g. 2020. MakeTCPConnection (XConnDis.c) tries to use this | as an IP address instead of a host name. | | What we'd like to do is change Xlib to interpret the hostname string as | a hostname first, and if there's no such host, interpret it as an IP | address ... I balk at changing the order because the following comment... | | /* | * if numeric host name then try to parse it as such; do the number | * first because some systems return garbage instead of INVALID_INETADDR | */ | | ...indicates that there was a good reason for the current order. From RFC-952, page 1 discussing the format of host names (among others): 1. A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.). Note that periods are only allowed when they serve to delimit components of "domain style names". (See RFC-921, "Domain Name System Implementation Schedule", for background). No blank or space characters are permitted as part of a name. No disinction is made between upper and lower case. The first character must be an alpha character. The last character must not be a minus sign or a period. ... (Note that RFC-1122 or RFC-1123 probably has something to say about this also but I *still* haven't had time to read through them. (sigh)) Thus, if a name begins with a non-alpha, it's not a ``host name''. It must be some other method of naming a host. If it begins with a numeric digit, it's a good guess that the host is being named via its IP address. Casey