Stuart, You don't tell us if it's www.linkedin.com or linkedin.com, but in any case, because they serve up that site around the world using some form of GLB it may resolve to different IP depending on where you are. From my perspective it is working via Cogent, and I can hit 108.174.2.129, too: root@nagios:# tcptraceroute www.linkedin.com Selected device eth0.3, address 96.31.0.5, port 43355 for outgoing packets Tracing the path to www.linkedin.com (199.101.163.129) on TCP port 80 (www), 30 hops max 1 router-core-inside.mtcnet.net (96.31.0.254) 0.253 ms 0.193 ms 0.203 ms 2 sxct.sxcy.mtcnet.net (167.142.156.197) 0.194 ms 0.131 ms 0.129 ms 3 premier.sxcy-mlx.fbnt.netins.net (173.215.60.5) 1.632 ms 1.601 ms 1.583 ms 4 38.104.184.26 7.004 ms 6.373 ms 6.437 ms 5 te0-0-1-1.rcr11.dsm01.atlas.cogentco.com (38.104.184.25) 5.913 ms 6.083 ms 5.877 ms 6 te0-2-0-0.ccr41.ord01.atlas.cogentco.com (154.54.46.237) 13.057 ms 13.114 ms 13.075 ms 7 be2156.ccr21.mci01.atlas.cogentco.com (154.54.6.85) 24.995 ms 24.942 ms 25.053 ms 8 be2012.ccr21.dfw01.atlas.cogentco.com (154.54.2.114) 35.013 ms 34.942 ms 34.928 ms 9 be2144.ccr21.iah01.atlas.cogentco.com (154.54.25.105) 40.455 ms 40.749 ms 40.709 ms 10 be2065.ccr21.lax01.atlas.cogentco.com (154.54.5.66) 76.269 ms 76.119 ms 75.970 ms 11 * * * 12 154.24.22.126 76.351 ms 76.296 ms 76.257 ms 13 38.88.244.2 73.135 ms 73.101 ms 73.182 ms 14 border1.po1-20g-bbnet1.lax008.pnap.net (216.52.255.46) 73.354 ms 73.355 ms 73.585 ms 15 linkedin-16.border1.lax008.pnap.net (216.52.220.122) 74.017 ms 74.005 ms 73.965 ms 16 * * * 17 199.101.162.226 74.766 ms 74.391 ms 74.582 ms 18 199.101.163.129 [open] 74.528 ms 74.381 ms 74.421 ms root@nagios:# root@nagios:/# tcptraceroute 108.174.2.129 Selected device eth0.3, address 96.31.0.5, port 49338 for outgoing packets Tracing the path to 108.174.2.129 on TCP port 80 (www), 30 hops max 1 router-core-inside.mtcnet.net (96.31.0.254) 0.295 ms 0.210 ms 0.237 ms 2 sxct.spnc.mtcnet.net (167.142.156.194) 0.206 ms 0.144 ms 0.129 ms 3 premier.spnc-mlx.fbnt.netins.net (173.215.60.1) 15.282 ms 4.743 ms 4.750 ms 4 ins-kb3-et-0-7-0-0.kmrr.netins.net.67.142.167.in-addr.arpa (167.142.67.50) 8.787 ms 8.705 ms 8.505 ms 5 ins-kc2-et-9-3.kmrr.netins.net (167.142.67.49) 7.170 ms 7.183 ms 7.189 ms 6 ins-dc1-po20.desm.netins.net (167.142.67.29) 7.623 ms 8.936 ms 8.135 ms 7 207.87.180.149 12.733 ms 52.226 ms 12.740 ms 8 ae1d0.mcr1.minneapolis-mn.us.xo.net (216.156.1.85) 23.368 ms 22.132 ms 22.052 ms 9 vb1710.rar3.chicago-il.us.xo.net (216.156.0.169) 22.984 ms 23.536 ms 24.016 ms 10 207.88.14.194.ptr.us.xo.net (207.88.14.194) 21.861 ms 21.882 ms 21.880 ms 11 206.111.2.65.ptr.us.xo.net (206.111.2.65) 23.583 ms 22.722 ms 22.876 ms 12 ae-8.r05.chcgil09.us.bb.gin.ntt.net (129.250.4.221) 22.630 ms 22.751 ms 22.817 ms 13 165.254.191.82 22.760 ms 22.726 ms 22.722 ms 14 * * * 15 * * * 16 108.174.2.129 [open] 36.065 ms 36.058 ms 36.042 ms root@nagios:/# root@nagios:/usr/lib/nagios/plugins# ./check_http -H www.linkedin.com -I 199.101.163.129 HTTP OK: HTTP/1.1 301 Moved Permanently - 1706 bytes in 0.167 second response time |time=0.166917s;;;0.000000 size=1706B;;;0 root@nagios:/usr/lib/nagios/plugins# root@nagios:/usr/lib/nagios/plugins# ./check_http -H www.linkedin.com -I 108.174.2.129 HTTP OK: HTTP/1.1 301 Moved Permanently - 1702 bytes in 0.088 second response time |time=0.088261s;;;0.000000 size=1702B;;;0 root@nagios:/usr/lib/nagios/plugins# Regards, Frank -----Original Message----- From: NANOG [mailto:nanog-bounces@nanog.org] On Behalf Of stuart clark Sent: Saturday, August 16, 2014 10:30 AM To: nanog@nanog.org Subject: Is LinkedIn down? Trace/tcptrace to 108.174.2.129 via Level3 - last hop is on the Linked/Level3 edge: 14 LINKEDIN-CO.edge3.Washington4.Level3.net (4.53.116.150) 76.034 ms 76.069 ms 76.066 ms Via telia.net 16 236 ms 221 ms * linkedin-ic-301441-ash-b1.c.telia.net [213.248.103.190] 17 * * * Request timed out. 18 259 ms 265 ms * 108.174.2.129 19 257 ms 299 ms 256 ms 108.174.2.129 No reply from LinkedIn support, but i see plenty of Verizon and Level3 customers cannot access LinkedIn for 24 hrs. 216.52.242.113 works ok. -SC (ASN25605)