How can I get true DNS TTL info into Squids IP cache?
If you have source for BIND, you can modify it as indicated in the diff below. It causes the global variable _dns_ttl_ to be set with the TTL of the most recent lookup. Then, when you compile Squid, the configure script will look for the _dns_ttl_ symbol in libresolv.a. If found, dnsserver will return the TTL value for every lookup. This hack was contributed by Endre Balint Nagy. diff -ru bind-4.9.4-orig/res/gethnamaddr.c bind-4.9.4/res/gethnamaddr.c — bind-4.9.4-orig/res/gethnamaddr.c Mon Aug 5 02:31:35 1996 +++ bind-4.9.4/res/gethnamaddr.c Tue Aug 27 15:33:11 1996 @@ -133,6 +133,7 @@ } align; extern int h_errno; +int _dns_ttl_; #ifdef DEBUG static void @@ -223,6 +224,7 @@ host.h_addr_list = h_addr_ptrs; haveanswer = 0; had_error = 0; + _dns_ttl_ = -1; while (ancount– > 0 && cp < eom && !had_error) { n = dn_expand(answer->buf, eom, cp, bp, buflen); if ((n < 0) || !(*name_ok)(bp)) { @@ -232,8 +234,11 @@ cp += n; /* name */ type = _getshort(cp); cp += INT16SZ; /* type */ - class = _g
