diff --git a/src/event/Loop.cxx b/src/event/Loop.cxx
index d7ffd834aa..ade789b098 100644
--- a/src/event/Loop.cxx
+++ b/src/event/Loop.cxx
@@ -18,6 +18,8 @@
 #include "io/uring/Queue.hxx"
 #endif
 
+#include <limits.h> // for INT_MAX
+
 #ifdef HAVE_URING
 
 class EventLoop::UringPoll final : Uring::Operation {
@@ -346,9 +348,14 @@ EventLoop::RunOneIdle() noexcept
 static constexpr int
 ExportTimeoutMS(Event::Duration timeout) noexcept
 {
-	return timeout >= timeout.zero()
-		? static_cast<int>(std::chrono::ceil<std::chrono::milliseconds>(timeout).count())
-		: -1;
+	if (timeout < timeout.zero())
+		return -1;
+
+	const auto ms = std::chrono::ceil<std::chrono::milliseconds>(timeout).count();
+	if (ms > INT_MAX)
+		return INT_MAX;
+
+	return static_cast<int>(ms);
 }
 
 #ifdef HAVE_URING
diff --git a/src/net/IPv4Address.cxx b/src/net/IPv4Address.cxx
index 1842aba6a2..7ace24e8ac 100644
--- a/src/net/IPv4Address.cxx
+++ b/src/net/IPv4Address.cxx
@@ -4,6 +4,12 @@
 #include "IPv4Address.hxx"
 
 #include <cassert>
+#include <cstring> // for strlen()
+#include <cstdio> // for sprintf()
+
+#ifndef _WIN32
+#include <arpa/inet.h> // for inet_ntop()
+#endif
 
 IPv4Address::IPv4Address(SocketAddress src) noexcept
 	:address(src.CastTo<struct sockaddr_in>())
@@ -11,3 +17,24 @@ IPv4Address::IPv4Address(SocketAddress src) noexcept
 	assert(!src.IsNull());
 	assert(src.GetFamily() == AF_INET);
 }
+
+const char *
+IPv4Address::Format(std::span<char> buffer) const noexcept
+{
+	if (buffer.size() <= 7) [[unlikely]]
+		return nullptr;
+
+	char *p = buffer.data();
+
+	if (inet_ntop(AF_INET, &address.sin_addr,
+		      p, buffer.size() - 7) == nullptr)
+		return nullptr;
+
+	const unsigned port = GetPort();
+	if (port != 0) {
+		p += std::strlen(p);
+		std::sprintf(p, ":%u", port);
+	}
+
+	return buffer.data();
+}
diff --git a/src/net/IPv4Address.hxx b/src/net/IPv4Address.hxx
index 3d96e4e0b0..e14ae729c1 100644
--- a/src/net/IPv4Address.hxx
+++ b/src/net/IPv4Address.hxx
@@ -232,4 +232,12 @@ public:
 		return IPv4Address(ConstructInAddrBE(GetNumericAddressBE() & other.GetNumericAddressBE()),
 				   GetPort() & other.GetPort());
 	}
+
+	/**
+	 * Format this object as a C string into the given buffer.
+	 *
+	 * @return the C string on success, nullptr on error
+	 */
+	[[nodiscard]]
+	const char *Format(std::span<char> buffer) const noexcept;
 };
diff --git a/src/net/IPv6Address.cxx b/src/net/IPv6Address.cxx
index 4689002242..a11f2dc9ca 100644
--- a/src/net/IPv6Address.cxx
+++ b/src/net/IPv6Address.cxx
@@ -5,8 +5,12 @@
 #include "IPv4Address.hxx"
 
 #include <cassert>
+#include <cstring> // for strlen()
+#include <cstdio> // for sprintf()
 
-#include <string.h>
+#ifndef _WIN32
+#include <arpa/inet.h> // for inet_ntop()
+#endif
 
 IPv6Address::IPv6Address(SocketAddress src) noexcept
 	:address(src.CastTo<struct sockaddr_in6>())
@@ -65,3 +69,27 @@ IPv6Address::operator&(const IPv6Address &other) const
 		     sizeof(result));
 	return result;
 }
+
+const char *
+IPv6Address::Format(std::span<char> buffer) const noexcept
+{
+	if (buffer.size() <= 9) [[unlikely]]
+		return nullptr;
+
+	char *p = buffer.data();
+
+	const unsigned port = GetPort();
+	if (port != 0)
+		*p++ = '[';
+
+	if (inet_ntop(AF_INET6, &address.sin6_addr,
+		      p, buffer.size() - 9) == nullptr)
+		return nullptr;
+
+	if (port != 0) {
+		p += std::strlen(p);
+		std::sprintf(p, "]:%u", port);
+	}
+
+	return buffer.data();
+}
diff --git a/src/net/IPv6Address.hxx b/src/net/IPv6Address.hxx
index f1377adc8f..85d5634a8d 100644
--- a/src/net/IPv6Address.hxx
+++ b/src/net/IPv6Address.hxx
@@ -212,6 +212,14 @@ public:
 	[[gnu::pure]]
 	IPv6Address operator&(const IPv6Address &other) const;
 
+	/**
+	 * Format this object as a C string into the given buffer.
+	 *
+	 * @return the C string on success, nullptr on error
+	 */
+	[[nodiscard]]
+	const char *Format(std::span<char> buffer) const noexcept;
+
 private:
 	/**
 	 * Helper function for MaskFromPrefix().
diff --git a/src/net/InetAddress.hxx b/src/net/InetAddress.hxx
index 946cb0201e..37bad170fe 100644
--- a/src/net/InetAddress.hxx
+++ b/src/net/InetAddress.hxx
@@ -10,6 +10,8 @@
 #include "IPv6Address.hxx"
 #endif
 
+#include <span>
+
 /**
  * A class that can store either an IPv4 or an IPv6 address.
  */
@@ -116,4 +118,26 @@ public:
 			return {};
 		}
 	}
+
+	/**
+	 * Format this object as a C string into the given buffer.
+	 *
+	 * @return the C string on success, nullptr on error
+	 */
+	[[nodiscard]]
+	const char *Format(std::span<char> buffer) const noexcept {
+		switch (GetFamily()) {
+		case AF_INET:
+			return v4.Format(buffer);
+
+#ifdef HAVE_IPV6
+		case AF_INET6:
+			return v6.Format(buffer);
+#endif
+
+		default:
+			[[unlikely]]
+			return nullptr;
+		}
+	}
 };