I invoked virt-isntall with --network=bridge:eth1 rather than --network=bridge:br1 and got the latter (current) diagnostic below. This change makes it so in this relatively common case people get a slightly more understandable diagnostic. From: Jim Meyering <meyering(a)redhat.com&gt; Date: Tue, 8 Jul 2008 13:58:10 +0200 Subject: [PATCH] give a more useful diagnostic for tap-add failure w/ENOTSUP * src/qemu_conf.c (qemudNetworkIfaceConnect): Suggestion from Daniel P. Berrange. --- src/qemu_conf.c | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) diff --git a/src/qemu_conf.c b/src/qemu_conf.c index 17f0162..4b8c01e 100644 --- a/src/qemu_conf.c +++ b/src/qemu_conf.c @@ -2304,9 +2304,17 @@ qemudNetworkIfaceConnect(virConnectPtr conn, if ((err = brAddTap(driver->brctl, brname, ifname, BR_IFNAME_MAXLEN, &tapfd))) { - qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, - _("Failed to add tap interface '%s' to bridge '%s' : %s"), - ifname, brname, strerror(err)); + if (errno == ENOTSUP) { + /* In this particular case, give a better diagnostic. */ + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, + _("Failed to add tap interface to bridge. " + "%s is not a bridge device"), brname); + } else { + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, + _("Failed to add tap interface '%s' " + "to bridge '%s' : %s"), + ifname, brname, strerror(err)); + } goto error; } -- 1.5.6.2.221.gb589