From owner-freebsd-net@freebsd.org Wed May 27 02:20:25 2020 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4834E2FB5E3 for ; Wed, 27 May 2020 02:20:25 +0000 (UTC) (envelope-from hongyi.zhao@gmail.com) Received: from mail-vs1-xe2b.google.com (mail-vs1-xe2b.google.com [IPv6:2607:f8b0:4864:20::e2b]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49WvgW6fKHz4PLn for ; Wed, 27 May 2020 02:20:23 +0000 (UTC) (envelope-from hongyi.zhao@gmail.com) Received: by mail-vs1-xe2b.google.com with SMTP id r10so559888vsa.12 for ; Tue, 26 May 2020 19:20:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=F6sOAezDceJnkZgmo+M2rBNgof9wttTAh9W16T4ndWc=; b=QwPBY3F4rJ0Leg1bPioqXIRNUpax+AXqROg8Ar8SpUWbXNLMH+0O8JbYfJnjaBQErt ldqnb/WTPfI1mjW0g5SwofYju48N4cS5fZwH00vpc3pNLqvzlgrHg3DbL6o3IZpNDCrR Mc5IR+f+WhzzUDD9Ehm4DLMPxEvR2U2MMn5NaoY3higT6oMOBVFCeAHxaoOAuLmDPKUw qd/M/YJm5uYHvDCTjqi9eWhObYXYLnoqvEM3Do3/HZecEy0R2HC8JyUAByswmS3RBicB KlHrE5logPlWeUA395KEOgSYkl3DIhrLVFx2KjOMPvaKBufrjHFGi9nf5hxwy6hqORXJ HxHg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=F6sOAezDceJnkZgmo+M2rBNgof9wttTAh9W16T4ndWc=; b=A6jqgdWNefisj+ZVkOsDfodGmttkyvwFAo06j7dXWZQnLXFrYAn8lbNf7sX21mDN3w c31UTgeY9bMyRrdK6IUQOA+3DFq7pHxYTyX/8ztVeaKqAQEdofc1loPE0MIudrOYScvl 579H5UdQJFGAuOTGe6P4Y6XBW15C9eCZDLLfWx27fakxOb1f63ZnzSRtly/c1j5vdzsL Kz+35us/Tw8JkSfcha0OYD6tHyvBQrNHeeUOMWeJL06UCcgXj4ji5LjajR+rjxUEkSWr L6BY1Hg8TBnUHAwf9Ni5Ac7FdxJlKqRb5XvBxqdE9uFM/l5sfptjBbThWCOePDIFF8en 5v6A== X-Gm-Message-State: AOAM533UL5XHFu6ZuOnMt06tIzMyxv6npy97q9qLY6Jn0Fb7AzCiMxdE T3ucoXsSZkmWSpBa4vFotbfal9rmnl1uBFq13ApEqXbTQ2mLBw== X-Google-Smtp-Source: ABdhPJzL8QWzZHpB2No+X+1zywBNUsFvOdzZU8tnYHPe7mUtSz/OkEq5Dnox8mScglQFkERaiIL+zTD5AOCRQwpsK3Q= X-Received: by 2002:a67:684a:: with SMTP id d71mr3181919vsc.176.1590546022909; Tue, 26 May 2020 19:20:22 -0700 (PDT) MIME-Version: 1.0 From: Hongyi Zhao Date: Wed, 27 May 2020 10:20:11 +0800 Message-ID: Subject: Check a no-auth socks5 proxy running on localhost's 18887 port with netcat. To: freebsd-net@freebsd.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 49WvgW6fKHz4PLn X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=QwPBY3F4; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of hongyizhao@gmail.com designates 2607:f8b0:4864:20::e2b as permitted sender) smtp.mailfrom=hongyizhao@gmail.com X-Spamd-Result: default: False [-3.34 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.01)[-1.013]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; R_SPF_ALLOW(-0.20)[+ip6:2607:f8b0:4000::/36:c]; FREEMAIL_FROM(0.00)[gmail.com]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; TO_DN_NONE(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; RCVD_IN_DNSWL_NONE(0.00)[2607:f8b0:4864:20::e2b:from]; NEURAL_HAM_SHORT(-0.33)[-0.326]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2607:f8b0::/32, country:US]; TAGGED_FROM(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 May 2020 02:20:25 -0000 Hi, I try to check a no-auth socks5 proxy running on localhost's 18887 port with netcat. Based on the notes here: https://stackoverflow.com/questions/52530515/how-use-netcat-to-test-socks5-server I obtained the following two usages: $ printf "\x05\x01\x00\r\n" | nc 127.0.0.1 18887 | hd 00000000 05 00 05 07 00 01 |......| 00000006 Does the first field represent serial number? And I also do the following test: werner@ubuntu-01:~$ printf "\x05\x01\x00\r\n" | /usr/bin/nc.traditional 127.0.0.1 18887 -o out.txt werner@ubuntu-01:~$ cat out.txt > 00000000 05 01 00 0d 0a # ..... < 00000000 05 00 # .. < 00000002 05 07 00 01 # .... Why the first two lines in the output have the same value for the first field? Regards -- Hongyi Zhao