Hi Wouters, > Since you did not compile with libevent, you do have a limit there, > certainly as compared to your 950 outgoing-range. If you used libevent, > you could simply state the number you want (it takes about 65k for every > buffer); so 100 or 200 would be a lot. How did you know/notice that libevent wasn't working ? Because I thought I was using it... Indeed when I increased num-tcp unbound complained about the 1024 files limit so obviously libevent is not used... But based on unbound -h and ldd output it looks like it is linked with libevent. Did I miss the documentation part "how to enable libevent in unbound.conf ?" Should I use more than one thread or is it a bug with old EL5 libraries ? Version 1.4.6 linked libs: libevent 1.4.13-stable (it uses epoll), ldns 1.6.6, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008 linked modules: validator iterator configured for i386-redhat-linux-gnu on Tue Aug 24 16:08:57 EST 2010 with options: '--build=i386-koji-linux-gnu' '--host=i386-koji-linux-gnu' '--target=i386-redhat-linux-gnu' '--program-prefix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--sysconfdir=/etc' '--datadir=/usr/share' '--includedir=/usr/include' '--libdir=/usr/lib' '--libexecdir=/usr/libexec' '--localstatedir=/var' '--sharedstatedir=/usr/com' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--with-ldns=' '--with-libevent' '--with-pthreads' '--with-ssl' '--disable-rpath' '--enable-debug' '--disable-static' '--with-conf-file=/etc/unbound/unbound.conf' '--with-pidfile=/var/run/unbound/unbound.pid' '--enable-sha2' BSD licensed, see LICENSE in source package for details. Report bugs to unbound-bugs at nlnetlabs.nl # ldd /usr/sbin/unbound libssl.so.6 => /lib/libssl.so.6 (0x00336000) libldns.so.1 => /usr/lib/libldns.so.1 (0x007cd000) libevent-1.4.so.2 => /usr/lib/libevent-1.4.so.2 (0x009fd000) librt.so.1 => /lib/librt.so.1 (0x00f96000) libcrypto.so.6 => /lib/libcrypto.so.6 (0x00110000) libc.so.6 => /lib/libc.so.6 (0x005ad000) libpthread.so.0 => /lib/libpthread.so.0 (0x00c3c000) libgssapi_krb5.so.2 => /usr/lib/libgssapi_krb5.so.2 (0x00251000) libkrb5.so.3 => /usr/lib/libkrb5.so.3 (0x0027e000) libcom_err.so.2 => /lib/libcom_err.so.2 (0x00314000) libk5crypto.so.3 => /usr/lib/libk5crypto.so.3 (0x0037e000) libresolv.so.2 => /lib/libresolv.so.2 (0x00b94000) libdl.so.2 => /lib/libdl.so.2 (0x00d86000) libz.so.1 => /usr/lib/libz.so.1 (0x00732000) libnsl.so.1 => /lib/libnsl.so.1 (0x00317000) /lib/ld-linux.so.2 (0x00894000) libkrb5support.so.0 => /usr/lib/libkrb5support.so.0 (0x00ab6000) libkeyutils.so.1 => /lib/libkeyutils.so.1 (0x00c12000) libselinux.so.1 => /lib/libselinux.so.1 (0x00b4f000) libsepol.so.1 => /lib/libsepol.so.1 (0x00dc7000) Cheers, Thomas