- Adjusted so-sndbuf default to 4m.

diff --git a/doc/Changelog b/doc/Changelog
index b7bcabb6d0c8960fd146021eb4bb3f47d8d5747b..dac34fd690b0a8252b5657e14d4aedb35ed03bcc 100644 (file)
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -7,6 +7,7 @@
        - Change default for so-sndbuf to 1m, to mitigate a cross-layer
          issue where the UDP socket send buffers are exhausted waiting
          for ARP/NDP resolution. Thanks to Reflyable for the report.
+       - Adjusted so-sndbuf default to 4m.
 
 12 May 2025: Yorgos
        - Merge #1280: Fix auth nsec3 code. Fixes NSEC3 code to not break on

diff --git a/doc/example.conf.in b/doc/example.conf.in
index c2bc6e9d849416596691cdc62f543643d8264cb7..a85b58de4327d20e28f1ea401531111e5f582592 100644 (file)
--- a/doc/example.conf.in
+++ b/doc/example.conf.in
@@ -116,8 +116,8 @@ server:
        # so-rcvbuf: 0
 
        # buffer size for UDP port 53 outgoing (SO_SNDBUF socket option).
-       # 0 is system default.  Use 4m to handle spikes on very busy servers.
-       # so-sndbuf: 1m
+       # 0 is system default. Set larger to handle spikes on very busy servers.
+       # so-sndbuf: 4m
 
        # use SO_REUSEPORT to distribute queries over threads.
        # at extreme load it could be better to turn it off to distribute even.

diff --git a/doc/unbound.conf.5.in b/doc/unbound.conf.5.in
index 3407b3414bc8f2c46f511d16e781019c7b42e0f7..c469c3c66139c827147d711b964c6f677d6796ba 100644 (file)
--- a/doc/unbound.conf.5.in
+++ b/doc/unbound.conf.5.in
@@ -355,8 +355,8 @@ If not 0, then set the SO_SNDBUF socket option to get more buffer space on
 UDP port 53 outgoing queries.  This for very busy servers handles spikes
 in answer traffic, otherwise 'send: resource temporarily unavailable'
 can get logged, the buffer overrun is also visible by netstat \-su.
-Default is 1M. If set to 0 it uses the system value. Specify the number
-of bytes to ask for, try "4m" on a very busy server. It needs some space
+Default is 4m. If set to 0 it uses the system value. Specify the number
+of bytes to ask for, try "8m" on a very busy server. It needs some space
 to be able to deal with packets that wait for local address resolution,
 from like ARP and NDP discovery, before they are sent out, hence
 it is elevated above the system default by default.  The OS caps it at

diff --git a/util/config_file.c b/util/config_file.c
index 328b62df8963c4cd4baf3d58b29a9d27dc2d009f..b1e767b3b2a71173fdae36d0b80d6ee34f45487e 100644 (file)
--- a/util/config_file.c
+++ b/util/config_file.c
@@ -210,7 +210,7 @@ config_create(void)
        cfg->if_automatic = 0;
        cfg->if_automatic_ports = NULL;
        cfg->so_rcvbuf = 0;
-       cfg->so_sndbuf = 1024*1024;
+       cfg->so_sndbuf = 4*1024*1024;
        cfg->so_reuseport = REUSEPORT_DEFAULT;
        cfg->ip_transparent = 0;
        cfg->ip_freebind = 0;