From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Wed, 23 Mar 2022 15:36:48 +0000 (-0400)
Subject: Adjust MIN_PORT to match other implementations
X-Git-Tag: v0.96~30^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F426%2Fhead;p=thirdparty%2Fmtr.git

Adjust MIN_PORT to match other implementations

Port 33434 is the IANA-reserved port for traceroute. It also seems to be
the most common start port. The following implementations, and
likely others, use it as their start port:

- Apple macOS traceroute
- FreeBSD traceroute
- GNU inetutils-traceroute
- Modern traceroute for Linux
- OpenBSD traceroute

The benefit to using a standard starting port is that some firewalls may
have these ports allowed, whereas other ports may be blocked, so there
is a greater probability the probe will succeed.
---

diff --git a/packet/probe_unix.h b/packet/probe_unix.h
index f217a66..f3e8207 100644
--- a/packet/probe_unix.h
+++ b/packet/probe_unix.h
@@ -25,7 +25,7 @@
 #endif
 
 /*  The range of local port numbers to use for probes  */
-#define MIN_PORT 33000
+#define MIN_PORT 33434
 #define MAX_PORT 65535
 
 /*  We need to track the transmission and timeouts on Unix systems  */