From f2e3662e57eca1330962faf38ff428a564d50a11 Mon Sep 17 00:00:00 2001
From: laanwj <126646+laanwj@users.noreply.github.com>
Date: Thu, 11 Apr 2024 14:38:32 +0200
Subject: [PATCH] net: Decrease nMaxIPs when learning from DNS seeds

Limit number of IPs learned from a single DNS seed to 32, to prevent the results from
one DNS seed from dominating AddrMan. Note that the number of results from a UDP DNS query is
bounded to 33 already, but it is possible for it to use TCP where a potentially enormous
number of results can be returned.

Closes #16070.
---
 src/net.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/net.cpp b/src/net.cpp
index e388f05b037ad..3e959c187c2c7 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2256,7 +2256,11 @@ void CConnman::ThreadDNSAddressSeed()
             if (!resolveSource.SetInternal(host)) {
                 continue;
             }
-            unsigned int nMaxIPs = 256; // Limits number of IPs learned from a DNS seed
+            // Limit number of IPs learned from a single DNS seed. This limit exists to prevent the results from
+            // one DNS seed from dominating AddrMan. Note that the number of results from a UDP DNS query is
+            // bounded to 33 already, but it is possible for it to use TCP where a larger number of results can be
+            // returned.
+            unsigned int nMaxIPs = 32;
             const auto addresses{LookupHost(host, nMaxIPs, true)};
             if (!addresses.empty()) {
                 for (const CNetAddr& ip : addresses) {