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<p>Hi,</p>
<p>Don't know if it is still actual for the original poster.</p>
<p>I've been encountered with it in Centos 6. Actually those messages are harmless since TCP just resends the packet with a correct checksum.</p>
<p>It seems to be a rhel6 kernel bug to me, not BIRDs. Moving to the recent version didn't help, but to Centos 7 did.</p>
<p><br /></p>
<p>Harish Shetty писал 2017-08-22 10:24:</p>
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<div>Hi All<br /><br /></div>
I am using bird-1.4.5-1.el6, we are getting alerted for TCP md5 authentication failures for almost on all the server's BGP peering with switches. Error we are seeing as mentioned below.<br />
<p>Jul 17 17:15:29 <a href="http://lca1-s1-csw02.nw.linkedin.com">lca1-s1-csw02.nw.linkedin.com</a> 2017 Jul 17 17:15:29 UTC: %NETSTACK-3-TCP_MD5_AUTH_FAILURE: netstack <span class="error">[3617]</span> MD5_DIGEST_INVALID:Dropping packets from src:x.x.x.x.34987,dst:y.y.y.yy.179</p>
<p>Jul 17 07:24:28 <a href="http://lca1-e1-csw01-lo0.nw.linkedin.com">lca1-e1-csw01-lo0.nw.linkedin.com</a> 2017 Jul 17 07:24:28 UTC: %NETSTACK-3-TCP_MD5_AUTH_FAILURE: netstack <span class="error">[3640]</span> MD5_DIGEST_INVALID:Dropping packets from src:yyyy.yyyy.yyyy.35088,dst:xxxx.xxxx.xxx.179</p>
<p><a href="http://lca1-s1-csw01.nw.linkedin.com">lca1-s1-csw01.nw.linkedin.com</a> 2017 Jul 17 05:01:25 UTC: %NETSTACK-3-TCP_MD5_AUTH_FAILURE: netstack <span class="error">[3617]</span> MD5_DIGEST_INVALID:Dropping packets from src:x.x.x.xx.55220,dst:1y.y.y.yy.179</p>
<p><br /></p>
<p>we have raised a Case with Cisco and they are saying possible cause would be "<span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"><span class="gmail-Apple-converted-space"> </span><span style="color: #000000;">If received packet has got modified in transit, so hash computed at origin is not matching at the destination". <br /></span></span></p>
<p><span style="color: #000000;"><span style="font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"> </span></span></p>
<p><span style="color: #000000;"><span style="font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;">Does anyone have seen this type of error before? Is bird causing something to corrupt the packet? Any solution / way to check and confirm everything fine at bird is appreciated.</span></span></p>
<p><span style="color: #000000;"><span style="font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"> </span></span></p>
<p><span style="color: #000000;"><span style="font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;">Regards</span></span></p>
<p><span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"><span style="color: #000000;">Harish Shetty</span><br /></span></p>
<p><span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"> </span></p>
<p><span style="color: #1f497d; font-family: Calibri,sans-serif; font-size: 14.6667px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; background-color: #ffffff; display: inline; float: none;"> </span></p>
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