{"id":2011,"date":"2025-06-30T11:08:45","date_gmt":"2025-06-30T10:08:45","guid":{"rendered":"https:\/\/blog.thomarite.uk\/?p=2011"},"modified":"2025-06-30T11:08:45","modified_gmt":"2025-06-30T10:08:45","slug":"jncia","status":"publish","type":"post","link":"https:\/\/blog.thomarite.uk\/index.php\/2025\/06\/30\/jncia\/","title":{"rendered":"JNCIA"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\">1<\/h1>\n\n\n\n<p>OSI:<br>7-app<br>6-present<br>5-session<br>4-transport<br>3-net<br>2-data-link<br>1-phy<\/p>\n\n\n\n<p>tcp\/ip<br>4-app<br>3-transport<br>2-internet\/network<br>1-link\/network access<\/p>\n\n\n\n<p>Please do<br>not throw<br>sausage pizza<br>away<\/p>\n\n\n\n<p>Armadilloes<br>take in<br>new ants<\/p>\n\n\n\n<p>MAC= Media Access Contor<br>LLC= Link Local Control<\/p>\n\n\n\n<p>L2 Header: preamble+sfd src mac, dst.mac, type data FCS<\/p>\n\n\n\n<p>L3 ipv4: Header 20B ipv6: header:<\/p>\n\n\n\n<p>L4: syn, sync-ack, ack<\/p>\n\n\n\n<p>hub=layer1 repeater<\/p>\n\n\n\n<p>qos: classification, marking, mgmt\/policy<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">2 Describe Ethernet and ipv4<\/h1>\n\n\n\n<p>binary\/decimal\/hexadecimal<\/p>\n\n\n\n<p>MAC address (48bits): OUI (24) + Interface ID (24)<\/p>\n\n\n\n<p>ipv4: 32b (8&#215;4)<\/p>\n\n\n\n<p>unicast, multicast, broadcast<br>01005E<br>224-239<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">3 Apply ipv4<\/h1>\n\n\n\n<p>subnetting\/supernetting<br>ARP<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">4 ipv6<\/h1>\n\n\n\n<p>128bits &#8211; 8xquartet(16b)<\/p>\n\n\n\n<p>broadcast: none!!!!!!!!!<br>multicast: MAC: 33-33:.. \/\/ FF00::\/8<br>link-local: always assigned, no routable: FE80::\/10 or \/64<br>unique local: like priv ip, routable internally. FC00::\/7 or FD00::\/8<br>global unicast: pub ip, routable internet 2000::\/3<\/p>\n\n\n\n<p>2001:1234:5678::\/48<br>2001:1234:5678:9abc::\/64<br>2001:1234:5678:9abc:d:e:f:0\/127<\/p>\n\n\n\n<p>NDP = Neighbor Discovery Protocol -&gt; ICMP + link-local + multicast.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Duplicate address detection (DAD)<\/li>\n\n\n\n<li>link layer address resolution<br>&#8212; Neighbor Solicitation: src.ip link-local dst.ip: solicited_node_ip (ff02::1:)<br>&#8212; Neigbor Advertisiemen:<\/li>\n<\/ul>\n\n\n\n<p>Router Discovery:<br>router solicitation: RS, request sent by host, dst.ip: FF02::2 (all routers) use link-local as src.ip<br>router advertisement: RA, reply sent by router, src.ip link-local, dst.ip = FF02::1 (all hosts in link-local). It contains global unicast range<\/p>\n\n\n\n<p>SLAAC: Stateless Address AutoConfiguration<br>1) obtain prefix through RA<br>2) host creates its own interface id.<br>2.1: use EUI-64: use MAC (48b) and filling -&gt; 1st half MAC + FFFE + 2nd half MAC + flip the 7th bit of the MAC.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">5 &#8211; Intro Juniper Cert and labs<\/h2>\n\n\n\n<p>OS fundamentals, user interface, configuration basics, operational monitoring and maintenance<br>routing fundamentasl, routing policy and firewall filters.<\/p>\n\n\n\n<p>lab: ex2200, vMX, vQFX, vSRX (kvm)<\/p>\n\n\n\n<p>juniper vlabs &#8211; are free!<\/p>\n\n\n\n<p>junos genius -&gt; get voucher for jncia, and train for -s and -p.<br>-&gt; day-one books!<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">6- Junos Arch<\/h2>\n\n\n\n<p>daemons<br>cp (routing-engine) vs dp (packet-fw-engine). fw-table is created by RE and then copied to the PFE<\/p>\n\n\n\n<p>exception traffic = non-transit traffic -&gt; goes to RE<br>PFE can handle ICMP responses<\/p>\n\n\n\n<p>major.minor.X = security (srx)<br>F = feature<br>R = bug fixes<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">7 Junos CLI<\/h2>\n\n\n\n<p>request system zeroize<br>mgd = mgmt daemon<br>\/config -&gt; junos config<\/p>\n\n\n\n<p>% -&gt; freebsd cli<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>-&gt; operationa mode<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">-&gt; config mode<\/h1>\n<\/blockquote>\n\n\n\n<p>show interfaces terse<\/p>\n\n\n\n<p>ctr-a -&gt; begining line<br>-e -&gt; end line<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>help tip cli<br>help topic x<br>help apropos interfaces<\/p>\n<\/blockquote>\n\n\n\n<p>show x | save var\/tmp\/text.txt<br>file show var\/tmp\/text\/txt<br>delet<br>show conf | display x<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">8 Create Junos Base Config<\/h2>\n\n\n\n<p>operator: clear network reset trace view<br>read-only: view<br>super-user: all<br>unauthorized: none<\/p>\n\n\n\n<p>snmp: privacy -&gt; priv+auth<br>auth -&gt; authNopriv<\/p>\n\n\n\n<p>[] -&gt; list<\/p>\n\n\n\n<p>syslog: timestamp hostname facility:message<br>set sytesm syslog file x host y<br>server -&gt; makes the device a syslog server !!!<br>0 emergency (kernel)<br>1 alert (user-space)<br>2 critical<br>3 error<br>4 warning<br>5 notice<br>6 info<br>7 any (debug)<\/p>\n\n\n\n<p>set vlans NAME vlan-id x<br>set interfaces ge-0\/0\/0 unit 0 family ethernet-switching port-mode access vlan members NAME<br>trunk vlan members [NAME1 NAME2]<br>srx -&gt; untrust \/ trust<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">9 Configure Junos Interfaces<\/h2>\n\n\n\n<p>set vlans NAME vlan-id 25<br>set interfaces vlan.25 family inet address IP\/24<br>set vlans NAME l3-interface vlan.25<\/p>\n\n\n\n<p>eui-64: use mac 48b<br>set address 2001:db8:dead:beef::\/65 eui-64<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">10 Junos config datastores<\/h2>\n\n\n\n<p>active config<br>configure -&gt; candidate config global<br>configure private -&gt; private candidate per user<br>configure exclusive -&gt; lock candidate for other users. No commited changes are lost after exit<br>request system configuration rescue save<br>rollback rescue<br>edit archival configuration<br>set archive-sites http\/ftp\/scp:user:pass@url<br>set transfer-on commit<\/p>\n\n\n\n<p>encrypt: aes\/des<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">11 Routing<\/h2>\n\n\n\n<p>inet.0 ipv4 unicast<br>inet.1 ipv4 multicasts<\/p>\n\n\n\n<p>RE: creates Routing table, then Forwarding table, then it is copied to the PFE<\/p>\n\n\n\n<p>1 &#8211; most specific<br>2 &#8211; lowest AD<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>0 directed  connect<\/code><\/pre>\n\n\n\n<p>AD: 5 static routes<br>10 ospf internal<br>15 isis<br>150 ospf ext<br>160 isis ext<br>170 bgp<\/p>\n\n\n\n<p>set routing-options static route DST\/x next-hop NH1<br>qualified-next-hop NH2 preference 7<\/p>\n\n\n\n<p>ospf:<br>224.0.0.5: hello<br>.6: DR<\/p>\n\n\n\n<p>edit protocols ospf<br>set area 0.0.0.0 interfaces X.0<\/p>\n\n\n\n<p>edit routing instance<br>set NAME_INSTANCE interface x.0<br>routing-options static route<br>protocols ospf area 0.0.0.2 interface y.0<\/p>\n\n\n\n<p>there are several types of routing-instances: ie:<br>vrf: for mpls, RD, RT, import\/export<br>virtual-router: no import\/expot, no rd,rt<\/p>\n\n\n\n<p>ipv6 static route:<br>edit routing-options<br>set rib inet6.0 static route X\/Y next-hop Z<\/p>\n\n\n\n<p>edit protocols ospf3<br>set area 0.0.0.0 iterface X.0<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">12 multi-vendor ospf<\/h2>\n\n\n\n<p>router id &#8211; hightest lo.IP or explicit<br>hello: router-id,<br>area-id,<br>timers (hello interval: 10 dead-interval: 40 (ethernet)),<br>area-types: stub, total-stub, nssa<br>mtu (stuck in ex-start)<\/p>\n\n\n\n<p>LSA-types:<\/p>\n\n\n\n<p>set routing-options router-id IP-Lo;<br>edit protocols<br>set ospf area 0.0.0.0 interface lo0.0;<\/p>\n\n\n\n<p>show ospf database: ID = LSA ID !!!!<\/p>\n\n\n\n<p>ref bw \/ interface bw = metric<\/p>\n\n\n\n<p>ref bw = 100 mpbs Juniper<\/p>\n\n\n\n<p>set protocols ospf reference-banwidth (bits per second!!!!)<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">13 Route policies<\/h2>\n\n\n\n<p>routing table modification: import\/export policies<br>route distribution: think of the perspective of the routing table<\/p>\n\n\n\n<p>edit policy-options<br>set policy-statement ISIS2OSPF from protocol isis then accept<br>from prefix-list NAME then xxx<br>from route-filter IP\/x orlonger<\/p>\n\n\n\n<p>set policy-statement TEST1 term T1 from protocol isis then accept<br>set policy-statement TEST1 term T2 from prefix-list NAME then tag 1<br>then accept<\/p>\n\n\n\n<p>edit protocols ospf<br>export ISIS2OSPF<\/p>\n\n\n\n<p>edit policy-options<br>set prefix-list PL IP\/x<\/p>\n\n\n\n<p>bgp:<br>edit policy-options<br>set policy-statement BGP-TEST1 then you can change\/add many BGP attributes<\/p>\n\n\n\n<p>default routing policies junos<br>bgp: default import: accept all<br>export: readvertise all (exception iBGP for split-horizon)<\/p>\n\n\n\n<p>mpls: default import: accept all<br>export: readvertise all<\/p>\n\n\n\n<p>isis: default import: accept all<br>export: reject everything<\/p>\n\n\n\n<p>ldp: default import: accept all<br>export: reject all<\/p>\n\n\n\n<p>ospf: default import: accept all (you can&#8217;t override this by ospf design)<br>export: reject all<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">14 Firewall Filter (ACLs) &#8211; no stateful !!! -&gt; need input\/output !!!<\/h2>\n\n\n\n<p>data-plane modification -&gt; accept, drop, QoS, change NH, RPF, logging, counting<\/p>\n\n\n\n<p>edit firewall<br>edit family inet<br>set filter NAME term T1 from source-addess IP\/32<br>from destination-port 80<br>then accept<br>term then discard (IMPLICIT!!!)<\/p>\n\n\n\n<p>edit interfaces xe-0\/0\/0 unit 0 family inet<br>set filter input FILTER-NAME<\/p>\n\n\n\n<p>discard -&gt; drop + no logging (silently)<br>reject -&gt; drop + sent ICMP<\/p>\n\n\n\n<p>qos:<br>policer<\/p>\n\n\n\n<p>edit firewall<br>set policer SSH-BE if-exceeding bandwithd-limit 100m then forwarding-class best-effort<\/p>\n\n\n\n<p>edit firewall family inet filter NAME<br>set term T1 then forwarding-class assured-forward<br>then policer SSH-BE<\/p>\n\n\n\n<p>RPF:<br>strict<br>loose<br>edit interfaces ge-0\/0\/0 unit 0 family inet<br>set rpf-check fail-filter NAME-FF<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">15- Operate and Maintain Junos<\/h2>\n\n\n\n<p>show system storage<br>alarms<br>commit<br>connections<br>statistics<\/p>\n\n\n\n<p>show chassis alarms<br>environment<br>hardware<br>routing-engine<\/p>\n\n\n\n<p>show virtual-chassis<\/p>\n\n\n\n<p>show chassis fpc<\/p>\n\n\n\n<p>show route table X.0 IP\/X extensive<\/p>\n\n\n\n<p>show interfaces ge-0\/0\/0.0 extensive<br>show interfaces ge-0\/0\/0 extensive -&gt; MAC address, CoS<\/p>\n\n\n\n<p>monitor interface ge-0\/0\/0 -&gt; statistics live<br>monitor interface traffic -&gt; all interfaces stats<br>monitor traffic interface ge-0\/0\/0.0 extensive -&gt; tcpdump<\/p>\n\n\n\n<p>request system halt -&gt; graceful shutdown<\/p>\n\n\n\n<p>request system storage cleanup dry-run<\/p>\n\n\n\n<p>request system software add \/var\/tmp\/xxxx.tgz reboot<\/p>\n\n\n\n<p>=================<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">JNCIA &#8211; Official training<\/h1>\n\n\n\n<p>Note: The process of moving routes between a routing protocol and the routing table is described always from the point of view of the routing table. That is, routes are imported into a routing table from a routing protocol and<br>routes are exported from a routing table to a routing protocol.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Intro JunOS on-demand<\/h2>\n\n\n\n<p>l2mtu: 1514s (ethernet header) _&gt; physical interface<\/p>\n\n\n\n<p>terse, brief, detail, extensive<\/p>\n\n\n\n<p>set cli screen-width 1000<\/p>\n\n\n\n<p>configure exclusive -&gt; lock for one user, but other users can&#8217;t commit<br>configure private -&gt; only commit from top, locks hierachy where you have made a change<br>commit at<br>clear system commit<\/p>\n\n\n\n<p>disable (put at the end) -&gt; interfaces and protocols -&gt; &#8220;delete \u2026. disable&#8221;<br>deactivate (put at the beginning) -&gt; nearly anything, it is commenting out a piece of config -&gt; use &#8220;activate&#8221;<\/p>\n\n\n\n<p>rename: rename address 1.1.1.1\/31 to address 1.1.1.11\/31<br>replace patten: replace pattern xe-0\/1\/2 with xe-0\/1\/4 (hierarchy aware!)<br>copy \/ move<br>insert<br>annotate<br>save<br>load<br>wildcard delete<\/p>\n\n\n\n<p>emacs short-cuts<br>ctr-w delete word<br>ctr-a &#8211; beginning<br>ctr-e &#8211; end<br>ctr-k &#8211; delete everything from cursor onwards<br>esc-b &#8211; backwards 1 word<br>esc-f &#8211; forwards 1 word<\/p>\n\n\n\n<p>show route -&gt; Local (ip configured in interface)s<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>= chosen active route between two or more protocols<\/li>\n<\/ul>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>= best path between two paths from the same protocol<\/p>\n<\/blockquote>\n\n\n\n<p>set routing-options static route IP\/23 next-hop IP<br>rib inet6.0 static route \u2026<\/p>\n\n\n\n<p>::\/0<\/p>\n\n\n\n<p>show route protocol static<\/p>\n\n\n\n<p>ospf =&gt; LSA<br>isis =&gt; LSPs<\/p>\n\n\n\n<p>set protocols ospf[3] area 0 inteface xe0\/0\/0.0 [passive]<\/p>\n\n\n\n<p>hello: 224.0.0.5, area, hello, dead=4xhello<\/p>\n\n\n\n<p>ospf3 -&gt; ipv6<\/p>\n\n\n\n<p>ex3400<\/p>\n\n\n\n<p>show configuration vlans<br>set vlans NAME vlan-id X<\/p>\n\n\n\n<p>set interfaces ge-0\/0\/0 unit 0 family ethernet-swtiching interface-mode [access|trunk]<br>vlan members [NAME1 NAME2]<\/p>\n\n\n\n<p>set interface ge-0\/0\/1 vlan-taggig !!!!<br>unit 10 vlan-id 10<br>family inet address IP1\/24<\/p>\n\n\n\n<p>show ethernet-switching table vlan NAME<\/p>\n\n\n\n<p>MistAI:<br>port securitu. loop preventio, poe, vc, macsec, evpn-vxlans<\/p>\n\n\n\n<p>missing vlans, wifi, port bounced, etc. onboaring, AI. Marvis (assistant)<br>wifi assurance, wired assurance, wan assurance<\/p>\n\n\n\n<p>mgmt port: fxp0, em0,<\/p>\n\n\n\n<p>manual<br>set system time-zone UTC<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>set date yyyymmddhhmm<\/p>\n<\/blockquote>\n\n\n\n<p>ntp<br>set system ntp server IP<br>show system uptime<br>show ntp associations<\/p>\n\n\n\n<p>set system name-server IP<\/p>\n\n\n\n<p>set system login user NAME class CLASS authentication encrypted-password xxxxx<br>$6$ -&gt; SHA-512<\/p>\n\n\n\n<p>super-user, unauthorized, operator (clear, view, reset, trace, network), read-only (view)<br>flags: all, clear, configure, network (ping, traceroute), view (no-config-show, system-wide, routing, protocol)<\/p>\n\n\n\n<p>j-web SRX, a few mx.<br>configure, monitor, status, upgrade<\/p>\n\n\n\n<p>set system service web-management https system-generated-certificate<\/p>\n\n\n\n<p>rs-232<\/p>\n\n\n\n<p>set system login messag &#8220;xxx&#8221; \/\/ before login<br>set system login annoucement (for after login) &#8220;xxxx&#8221;<\/p>\n\n\n\n<p>delete system commit factory-settings<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>request system configuration rescue save<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">rollbackc rescue<\/h1>\n\n\n\n<p>request system reboot\/halt [both-routing-engines]<\/p>\n<\/blockquote>\n\n\n\n<p>ztp<br>dhcp (DORA)<br>discover(broadcast)<br>offer<br>request: replies with the same ip info<br>acknowledge:<\/p>\n\n\n\n<p>dhcp-options:<\/p>\n\n\n\n<p>routing-engine: CPU, monitoring, mgmt, system, chassis, protocol, routing, junos, ping\/traceroute<br>writw forwarding-table and send to data-plane (NH IP, MAC and out interface))<\/p>\n\n\n\n<p>RIB, FIB<\/p>\n\n\n\n<p>PFE: muscle. ASIC (&lt;&gt; CPU) Express &#8211; PTX, Trio &#8211; MX<br>look-up, forward traffic, manipulate (ethernet headers, vlans, TTL)<br>cos: rate-limit, fw filters, priority<\/p>\n\n\n\n<p>exception traffic: traffic to\/from RE (loopback), ssh, protocols, ping, ARP, SNMP. TTL, ICMP replies<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>some PFE CPU can handle some exception traffic.<\/li>\n<\/ul>\n\n\n\n<p>start shell<br>daemos: routing (rpd), chassis, interfaces, mgmt (mgd), snmp, dcd (device control daemon), ppmd (periodic packet mgmt daemon)<\/p>\n\n\n\n<p>junos EVO<br>basedon linux, whitebox, integrate with 3rd party<br>daemons are individual apps, independently of evo, data is stored in distributed database, apps can be restarted without losing state<\/p>\n\n\n\n<p>syslog:<br>facility:severity:destinatin<br>show log FILENAME<br>show log interactive-commands | match USER<\/p>\n\n\n\n<p>monitor start messages -&gt; real time<br>monotor stop<\/p>\n\n\n\n<p>help syslog CODE_MESSAGE<\/p>\n\n\n\n<p>set system syslog host IP any notice<\/p>\n\n\n\n<p>severity:<br>0 emergency<br>1 alert<br>2 critical<br>3 error<br>4 warning<br>5 notice<br>6 info<br>7 any<\/p>\n\n\n\n<p>ping IP size PAYLOAD!!! (it is not MTU, it doesn include icmp header = 8, ip header=20b) so for mtu=1500 you need payload 1472<br>output shows the size of payload+icmo header only !!!!<\/p>\n\n\n\n<p>traceroute doesnt show return path!!!<\/p>\n\n\n\n<p>show ipv6 neighbors (via NDP)<\/p>\n\n\n\n<p>monitor interfce traffic -&gt; real time stats all interaces<br>monitor interface xe-0\/1\/5 -&gt; real time stts interface with errors<br>monitor traffic interface xe-0\/1\/5 -&gt; tcpdump<\/p>\n\n\n\n<blockquote class=\"wp-block-quote is-layout-flow wp-block-quote-is-layout-flow\">\n<p>help apropos COMMAD (fnd command)<br>help topic ospf dead-interval (documentation)<br>help referece ospf aread (configuration syntax reminders)<\/p>\n<\/blockquote>\n\n\n\n<p>statefull -&gt;hw fw &#8212; security policies<br>stateless -&gt; check per packet, no idea about session, lighter load &#8212; firewall filters (ACL)<\/p>\n\n\n\n<p>term -&gt; from: 0+ match conditions -&gt; then: 1+ actions<\/p>\n\n\n\n<p>match -&gt; nearlu any field in header ipv4,6 and ethernet<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>same condition -> OR (match source IP1, match source IP2)<\/li>\n\n\n\n<li>diff condition -> AND (match source IP, match dst port 343) discard -> drop silent<br>reject -> drop + icmp unreachable<\/li>\n<\/ul>\n\n\n\n<p>enable count, sample, duplicate, policing (rate-limit), cos, redirect, load-balance<\/p>\n\n\n\n<p>default in fw filter: discard -&gt; implicit term<\/p>\n\n\n\n<p>set firewall family inet filter NAME term TERM from CONDITIONS then AcTIONS<\/p>\n\n\n\n<p>show config firewall family inet filter XXX | display set relative<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>count\/log has &#8220;accept&#8221; implicit<\/li>\n<\/ul>\n\n\n\n<p>trade-offs<\/p>\n\n\n\n<p>set interface xe-0\/1\/4 unit 0 famiy inet filter output NAME<\/p>\n\n\n\n<p>show fiewall counter COUNTER filter NAME<\/p>\n\n\n\n<p>insert firewall family inter filter NAME term TERMy before\/after term TERMx<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>set firewall family inet filter NAME apply-flags omit -&gt; doesnt show i<br>set protocols ospf apply-flags omit -&gt; doesnt show (hidden command<\/p>\n\n\n\n<p>show omit -&gt; display set or display omit<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>protect protocols lldp -&gt; lock config, can&#8217;t delete<br>unprotect protocols lldp<\/p>\n\n\n\n<p>&#8212;<\/p>\n\n\n\n<p>annonate system &#8220;comment&#8221;<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>file list \/var\/log<br>file show FILE<br>show commands | save LOG.txt<br>show config | compare FILE1<br>file compare files FILE1 FILE2<\/p>\n\n\n\n<p>&#8212;<\/p>\n\n\n\n<p>load override terminal &#8211;&gt; replace entirely config via CLI<br>load merge terminal [relative] -&gt; add your config to the current config<\/p>\n\n\n\n<p>load merge|override FILE.txt<\/p>\n\n\n\n<p>load set terminal<\/p>\n\n\n\n<p>&#8212;<\/p>\n\n\n\n<p>set system archival configuration transfer-on-commit<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>set groups MTU_9192 interfaces mtu 9192<br>set interfaces apply-groups MTU_9192<br>set interfaces xxxx apply-groups-except MTU_9192<\/p>\n\n\n\n<p>show .. | display set | display inheritance [no-comments]<\/p>\n\n\n\n<p>edit interfaces interfaces-range RANGE<br>set member-range ge-0\/0\/10 to ge-0\/0\/12<br>set unit 0 family ethernet-switching vlan members VLAN<\/p>\n\n\n\n<p>wildcard delete interface xe-0\/1\/*<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>loopback:<br>set interfaces lo0 unit 0 family inet address ip\/32<br>set protocols ospa area 0 interface lo0.0<\/p>\n\n\n\n<p>RE protection -&gt; firewall filter in lo0<\/p>\n\n\n\n<p>router-id: lowest lo0 ip<\/p>\n\n\n\n<p>irb: integrated routing and bridging -&gt; default fw for vlan<\/p>\n\n\n\n<p>set interfaces irb unit 10 family inet address ip1\/24<br>20 \u2026<br>set vlans NAME l3-interface irb.10<br>NAME2 20<\/p>\n\n\n\n<p>show vlans NAM detail -&gt;shows irb<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>Several IPs in interface:<br>Is-preferred: the source to devices in the same subnet (lowes IP in subnet)<br>Is-Primary: the source to devices on a different subnet. (lowest IP from all subnets)<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>ecmp: equal-cost multipath<\/p>\n\n\n\n<p>LAG: link agg groups: LB per flow<br>set chassis aggregated-devices ethernet device-count X (&gt;=1)<\/p>\n\n\n\n<p>set interfces ae0 unit 0 family inet address x<br>aggregated-ether-options lacp active<\/p>\n\n\n\n<p>set interfaces ge-0\/0\/0 gigether-options 802.3ad ae0<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>automation:<br>XPATH<br>netconf<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>set policy-options prefix-list DIRECT apply-path &#8220;interfaces &lt;<em>&gt; unit &lt;<\/em>&gt; family inet addres &lt;*&gt;&#8221;<\/p>\n\n\n\n<p>firewall filter: match-codition+(-except) -&gt; protocol-except udp, destination-port-except 443, et<\/p>\n\n\n\n<p>log + count =&gt; implicit &#8220;accept&#8221; but you can use &#8220;next term&#8221;<\/p>\n\n\n\n<p>show firewall log<\/p>\n\n\n\n<p>show class-of-service forwarding-class<\/p>\n\n\n\n<p>show route forwarding-table destination IP\/x table default<\/p>\n\n\n\n<p>authentication order: if one fails\/unreachable, check with the following. If all unreachable, checks local<\/p>\n\n\n\n<p>custom login commands: (command1) | (command2)<\/p>\n\n\n\n<p>order: permissions -&gt; deny-commands\/config -&gt; allow-command\/config (allow override deny!!!)<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>1 OSI:7-app6-present5-session4-transport3-net2-data-link1-phy tcp\/ip4-app3-transport2-internet\/network1-link\/network access Please donot throwsausage pizzaaway Armadilloestake innew ants MAC= Media Access ContorLLC= Link Local Control L2 Header: preamble+sfd src mac, dst.mac, type data FCS L3 ipv4: Header 20B ipv6: header: L4: syn, sync-ack, ack hub=layer1 repeater qos: classification, marking, mgmt\/policy 2 Describe Ethernet and ipv4 binary\/decimal\/hexadecimal MAC address (48bits): OUI (24) + &hellip; <a href=\"https:\/\/blog.thomarite.uk\/index.php\/2025\/06\/30\/jncia\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;JNCIA&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-2011","post","type-post","status-publish","format-standard","hentry","category-networks"],"_links":{"self":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/2011","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/comments?post=2011"}],"version-history":[{"count":1,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/2011\/revisions"}],"predecessor-version":[{"id":2012,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/posts\/2011\/revisions\/2012"}],"wp:attachment":[{"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/media?parent=2011"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/categories?post=2011"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.thomarite.uk\/index.php\/wp-json\/wp\/v2\/tags?post=2011"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}