Okay if you have ever worked in a place where their network was complete choas with no documentation or network maps to help you figure out where something resides.<\/p>\n
You can sometimes use tcpdump to help you figure out where the server is sitting by using tcpdump. tcpdump -nn -v -i <NIC_INTERFACE> -s 1500 -c 1 ‘ether[20:2] == 0x2000’<\/em><\/p>\n Example<\/strong>:<\/p>\n root@ansible<\/span>:~ # <\/span>tcpdump<\/span> –<\/span>nn<\/span> -v –<\/span>i<\/span> eth<\/span>0<\/span> -s 1500 -c 1 ‘ether[20:2] == 0x2000’<\/span><\/em> Written by Nick Tailor<\/p>\n","protected":false},"excerpt":{"rendered":" Okay if you have ever worked in a place where their network was complete choas with no documentation or network maps to help you figure out where something resides. You can sometimes use tcpdump to help you figure out where the server is sitting by using tcpdump. Syntax tcpdump -nn -v -i <NIC_INTERFACE> -s 1500 -c 1 ‘ether[20:2] == 0x2000’Read More …<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[138,124],"tags":[],"class_list":["post-1042","post","type-post","status-publish","format-standard","hentry","category-linux","category-network-stuff"],"_links":{"self":[{"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/posts\/1042","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/comments?post=1042"}],"version-history":[{"count":3,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/posts\/1042\/revisions"}],"predecessor-version":[{"id":1595,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/posts\/1042\/revisions\/1595"}],"wp:attachment":[{"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/media?parent=1042"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/categories?post=1042"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/nicktailor.com\/tech-blog\/wp-json\/wp\/v2\/tags?post=1042"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n
\nSyntax<\/span><\/strong><\/p>\n
\n<\/em><\/em><\/p>\n
\ntcpdump<\/span>: listening on eth3, link-type EN10MB (Ethernet), capture size 1500 bytes<\/span><\/em>
\n03:25:22.146564 CDPv2, <\/span>ttl<\/span>: 180s, checksum: 692 (unverified), length 370<\/span><\/em>
\n Device-ID (0x01), length: 11 bytes: <\/span>‘<\/span>switch<\/span>-sw<\/span>02<\/span>‘ <\/span><\/strong><\/em>
\n Address (0x02), length: 13 bytes: IPv4 (1) 192.168.1.15<\/span><\/em>
\n Port-ID (0x03), length: 15 bytes:<\/span> <\/span>‘Ethernet0\/<\/span>1<\/span>‘<\/span><\/strong><\/em>
\n Capability (0x04), length: 4 bytes: (0x00000028): L2 Switch, IGMP snooping<\/span><\/em>
\n Version String (0x05), length: 220 bytes:<\/span><\/em>
\n Cisco Internetwork Operating System Software<\/span><\/em>
\n IOS ™ C2950 Software (C2950-I6Q4L2-M), Version 12.1(14)EA1a, RELEASE SOFTWARE (fc1)<\/span><\/em>
\n Copyright (c) 1986-2003 by cisco Systems, Inc.<\/span><\/em>
\n Compiled Tue 02-Sep-03 03:33 by <\/span>Nicola tesla<\/span><\/em>
\n Platform (0x06), length: 18 bytes: ‘cisco WS-C2950T-24’<\/span><\/em>
\n Protocol-Hello option (0x08), length: 32 bytes:<\/span><\/em>
\n VTP Management Domain (0x09), length: 6 bytes: ‘<\/span>ecomrd<\/span>‘<\/span><\/em>
\n Duplex (0x0b), length: 1 byte: full<\/span><\/em>
\n AVVID trust bitmap (0x12), length: 1 byte: 0x00<\/span><\/em>
\n AVVID untrusted ports <\/span>CoS<\/span> (0x13), length: 1 byte: 0x00<\/span><\/em>
\n1 packets captured<\/span><\/em>
\n2 packets received by filter<\/span><\/em>
\n0 packets dropped by kernel
\n<\/span><\/em>
\nroot@ansible:~ #<\/span><\/p>\n