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Diffstat (limited to 'FAQ')
| -rw-r--r-- | FAQ | 21 |
1 files changed, 21 insertions, 0 deletions
@@ -409,6 +409,27 @@ A: Yes, as a DNS server, dnsmasq will just work in a vserver. refer to the vserver documentation for more information). +Q: What's the problem with syslog and dnsmasq? + +A: In almost all cases: none. If you have the normal arrangement with + local daemons logging to a local syslog, which then writes to disk, + then there's never a problem. If you use network logging, then + there's a potential problem with deadlock: the syslog daemon will + do DNS lookups so that it can log the source of log messages, + these lookups will (depending on exact configuration) go through + dnsmasq, which also sends log messages. With bad timing, you can + arrive at a situation where syslog is waiting for dnsmasq, and + dnsmasq is waiting for syslog; they will both wait forever. This + problem is fixed from dnsmasq-2.39, which introduces asynchronous + logging: dnsmasq no longer waits for syslog and the deadlock is + broken. There is a remaining problem in 2.39, where "log-queries" + is in use. In this case most DNS queries generate two log lines, if + these go to a syslog which is doing a DNS lookup for each log line, + then those queries will in turn generate two more log lines, and a + chain reaction runaway will occur. To avoid this, use syslog-ng + and turn on syslog-ng's dns-cache function. + + |