I'm having some name lookup weirdness and not sure of the cause. Thought I'd post the scenario to the group before I start tweaking my configuration to see if it can be fixed. First off, I'm running syslog-ng 1.6.0rc3, and on the systems I'm having problems, they are Sun Netra systems, dual procs, 2GB of memory, running Solaris 8. My options look like this: log_fifo_size(2048); time_reopen(10); use_fqdn(yes); keep_hostname(no); use_dns(yes); dns_cache(yes); long_hostnames(off); I have 2 servers with this configuration acting as centralized loghosts for a datacenter. They are identical boxes, running identical syslog-ng configurations, on the same VLAN as the DNS servers they point to. Both of these boxes will periodically fail to lookup a name? and log an entry under it's IP address instead of it's fully qualified host name. There appears to be no pattern what so ever to it, and the log entries that get logged by IP are different on each syslog-ng server. The load on these systems is pretty minimal. The number of messages logged by IP address is averaging about 10 a day out of about 13000 messages being logged. To make things even more interesting, I have a similar setup in another datacenter, but they are older smaller systems, only Ultra 1's, single proc, with only 128 MB of memory, running Solaris 2.6, acting as centralized servers for about 3 times the number of servers. The syslog-ng version and configuration is identical. On these systems I can not find any entries logged by IP address, everything appears to be working fine. Any ideas what might be causing this? My gut reaction is to blame it on the DNS boxes since the problem is only happening in one data center and not another, but wanted to see if anyone else has already been down this road first. Thanks Rob Glasser AT&T Wireless UNIX Systems Administrator