{ "version": "https://jsonfeed.org/version/1.1", "user_comment": "This feed allows you to read the posts from this site in any feed reader that supports the JSON Feed format. To add this feed to your reader, copy the following URL -- https://matoken.org/blog/tag/dhcp/feed/json/ -- and add it your reader.", "home_page_url": "https://matoken.org/blog/tag/dhcp/", "feed_url": "https://matoken.org/blog/tag/dhcp/feed/json/", "language": "ja", "title": "dhcp – matoken's blog", "description": "Is there no plan B?", "icon": "https://matoken.org/blog/wp-content/uploads/2025/03/cropped-1865f695c4eecc844385acef2f078255036adccd42c254580ea3844543ab56d9.jpeg", "items": [ { "id": "http://matoken.org/blog/?p=2374", "url": "https://matoken.org/blog/2019/04/10/a-memo-to-capture-dhcp-packets/", "title": "dhcp \u30d1\u30b1\u30c3\u30c8\u3092\u30ad\u30e3\u30d7\u30c1\u30e3\u3059\u308b\u30e1\u30e2", "content_html": "
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tcpdump\u306e\u5834\u5408
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$ sudo tcpdump -i wlp3s0 port 67 or port 68 -e -n\r\n[sudo] password for matoken:\r\ntcpdump: verbose output suppressed, use -v or -vv for full protocol decode\r\nlistening on wlp3s0, link-type EN10MB (Ethernet), capture size 262144 bytes\r\n21:07:44.898511 00:23:15:5b:a6:60 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:23:15:5b:a6:60, length 300\r\n
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dhcpdump \u3082\u8aad\u307f\u3084\u3059\u304f\u3066\u4fbf\u5229
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$ sudo dhcpdump -i wlp3s0\r\n  TIME: 2019-04-10 21:17:17.398\r\n\tIP: 0.0.0.0 (0:23:15:5b:a6:60) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)\r\n\tOP: 1 (BOOTPREQUEST)\r\n HTYPE: 1 (Ethernet)\r\n  HLEN: 6\r\n  HOPS: 0\r\n   XID: 011d073a\r\n  SECS: 0\r\n FLAGS: 0\r\nCIADDR: 0.0.0.0\r\nYIADDR: 0.0.0.0\r\nSIADDR: 0.0.0.0\r\nGIADDR: 0.0.0.0\r\nCHADDR: 00:23:15:5b:a6:60:00:00:00:00:00:00:00:00:00:00\r\n SNAME: .\r\n FNAME: .\r\nOPTION:  53 (  1) DHCP message type         3 (DHCPREQUEST)\r\nOPTION:  50 (  4) Request IP address        192.168.1.5\r\nOPTION:  12 (  5) Host name                 x201i\r\nOPTION:  55 ( 17) Parameter Request List      1 (Subnet mask)\r\n\t\t\t\t\t\t\t\t\t\t\t 28 (Broadcast address)\r\n\t\t\t\t\t\t\t\t\t\t\t  2 (Time offset)\r\n\t\t\t\t\t\t\t\t\t\t\t  3 (Routers)\r\n\t\t\t\t\t\t\t\t\t\t\t 15 (Domainname)\r\n\t\t\t\t\t\t\t\t\t\t\t  6 (DNS server)\r\n\t\t\t\t\t\t\t\t\t\t\t119 (Domain Search)\r\n\t\t\t\t\t\t\t\t\t\t\t 12 (Host name)\r\n\t\t\t\t\t\t\t\t\t\t\t 44 (NetBIOS name server)\r\n\t\t\t\t\t\t\t\t\t\t\t 47 (NetBIOS scope)\r\n\t\t\t\t\t\t\t\t\t\t\t 26 (Interface MTU)\r\n\t\t\t\t\t\t\t\t\t\t\t121 (Classless Static Route)\r\n\t\t\t\t\t\t\t\t\t\t\t 42 (NTP servers)\r\n\t\t\t\t\t\t\t\t\t\t\t249 (MSFT - Classless route)\r\n\t\t\t\t\t\t\t\t\t\t\t 33 (Static route)\r\n\t\t\t\t\t\t\t\t\t\t\t252 (MSFT - WinSock Proxy Auto Detect)\r\n\t\t\t\t\t\t\t\t\t\t\t 17 (Root path)\r\n\r\n\r\n--------------------\r\n\r\n\r\n^C
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\n", "content_text": "tcpdump\u306e\u5834\u5408\n\n$ sudo tcpdump -i wlp3s0 port 67 or port 68 -e -n\r\n[sudo] password for matoken:\r\ntcpdump: verbose output suppressed, use -v or -vv for full protocol decode\r\nlistening on wlp3s0, link-type EN10MB (Ethernet), capture size 262144 bytes\r\n21:07:44.898511 00:23:15:5b:a6:60 > ff:ff:ff:ff:ff:ff, ethertype IPv4 (0x0800), length 342: 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 00:23:15:5b:a6:60, length 300\r\n\n\n\n\ndhcpdump \u3082\u8aad\u307f\u3084\u3059\u304f\u3066\u4fbf\u5229\n\n$ sudo dhcpdump -i wlp3s0\r\n TIME: 2019-04-10 21:17:17.398\r\n\tIP: 0.0.0.0 (0:23:15:5b:a6:60) > 255.255.255.255 (ff:ff:ff:ff:ff:ff)\r\n\tOP: 1 (BOOTPREQUEST)\r\n HTYPE: 1 (Ethernet)\r\n HLEN: 6\r\n HOPS: 0\r\n XID: 011d073a\r\n SECS: 0\r\n FLAGS: 0\r\nCIADDR: 0.0.0.0\r\nYIADDR: 0.0.0.0\r\nSIADDR: 0.0.0.0\r\nGIADDR: 0.0.0.0\r\nCHADDR: 00:23:15:5b:a6:60:00:00:00:00:00:00:00:00:00:00\r\n SNAME: .\r\n FNAME: .\r\nOPTION: 53 ( 1) DHCP message type 3 (DHCPREQUEST)\r\nOPTION: 50 ( 4) Request IP address 192.168.1.5\r\nOPTION: 12 ( 5) Host name x201i\r\nOPTION: 55 ( 17) Parameter Request List 1 (Subnet mask)\r\n\t\t\t\t\t\t\t\t\t\t\t 28 (Broadcast address)\r\n\t\t\t\t\t\t\t\t\t\t\t 2 (Time offset)\r\n\t\t\t\t\t\t\t\t\t\t\t 3 (Routers)\r\n\t\t\t\t\t\t\t\t\t\t\t 15 (Domainname)\r\n\t\t\t\t\t\t\t\t\t\t\t 6 (DNS server)\r\n\t\t\t\t\t\t\t\t\t\t\t119 (Domain Search)\r\n\t\t\t\t\t\t\t\t\t\t\t 12 (Host name)\r\n\t\t\t\t\t\t\t\t\t\t\t 44 (NetBIOS name server)\r\n\t\t\t\t\t\t\t\t\t\t\t 47 (NetBIOS scope)\r\n\t\t\t\t\t\t\t\t\t\t\t 26 (Interface MTU)\r\n\t\t\t\t\t\t\t\t\t\t\t121 (Classless Static Route)\r\n\t\t\t\t\t\t\t\t\t\t\t 42 (NTP servers)\r\n\t\t\t\t\t\t\t\t\t\t\t249 (MSFT - Classless route)\r\n\t\t\t\t\t\t\t\t\t\t\t 33 (Static route)\r\n\t\t\t\t\t\t\t\t\t\t\t252 (MSFT - WinSock Proxy Auto Detect)\r\n\t\t\t\t\t\t\t\t\t\t\t 17 (Root path)\r\n\r\n\r\n--------------------\r\n\r\n\r\n^C", "date_published": "2019-04-10T22:13:26+09:00", "date_modified": "2019-04-10T22:16:01+09:00", "authors": [ { "name": "matoken", "url": "https://matoken.org/blog/author/matoken/", "avatar": "https://secure.gravatar.com/avatar/38f5f3b575c5eb45cda6aa659bca119ac7a5e16b46565e869d0030e3bd66981d?s=512&d=mm&r=g" } ], "author": { "name": "matoken", "url": "https://matoken.org/blog/author/matoken/", "avatar": "https://secure.gravatar.com/avatar/38f5f3b575c5eb45cda6aa659bca119ac7a5e16b46565e869d0030e3bd66981d?s=512&d=mm&r=g" }, "tags": [ "dhcp", "packet capture", "tcpdump", "Debian", "Linux", "sid" ] } ] }