From 37cbfcce1426e9b53cd235d2c7f9f6740f4c467c Mon Sep 17 00:00:00 2001 From: Gernot Hillier Date: Thu, 10 Jul 2014 16:01:25 +0200 Subject: [PATCH] doc: slirp supports ICMP echo if enabled in Linux Since QEMU 0.15, slirp (user mode networking) supports ping to the Internet, see e6d43cfb1f9 Signed-off-by: Gernot Hillier Signed-off-by: Michael Tokarev --- qemu-doc.texi | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/qemu-doc.texi b/qemu-doc.texi index 551619abd7..2b232ae8b7 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -1205,9 +1205,16 @@ In order to check that the user mode network is working, you can ping the address 10.0.2.2 and verify that you got an address in the range 10.0.2.x from the QEMU virtual DHCP server. -Note that @code{ping} is not supported reliably to the internet as it -would require root privileges. It means you can only ping the local -router (10.0.2.2). +Note that ICMP traffic in general does not work with user mode networking. +@code{ping}, aka. ICMP echo, to the local router (10.0.2.2) shall work, +however. If you're using QEMU on Linux >= 3.0, it can use unprivileged ICMP +ping sockets to allow @code{ping} to the Internet. The host admin has to set +the ping_group_range in order to grant access to those sockets. To allow ping +for GID 100 (usually users group): + +@example +echo 100 100 > /proc/sys/net/ipv4/ping_group_range +@end example When using the built-in TFTP server, the router is also the TFTP server.