<div dir="ltr"><div>Yes, there's really a need for mechanisms of high availability like corosync, vrrp etc. Another simple example: we have two servers with the active/standby HA configuration (for example keepalived + haproxy) and we have third-party monitoring system for these servers. The monitoring system gets some load metrics and when one of the servers is unavailable, the monitoring system scales architecture (adds new server to cluster) in this way saving the HA architecture. In your case, this monitoring system must do the following steps: create new instance, add new instance's MAC address to allowed_address_pairs and only after that reconfigure all other nodes. Otherwise cluster will not work. The solution to the problem is simple - disable the prevent ARP spoofing mechnism.</div><div><br></div><div>Ok, we may used port_security options for this network with the HA cluster. For this case we must reconfigure our monitoring systems, create allowed_address_pairs for all current servers and (it's hardest) train our users how that done.</div><div><br></div><div>Currently, we don't use the prevent ARP spoofing option (prevent_arp_spoofing = False) and honestly I don't understand why this option is enabled as default in private networks. Each such network belongs to one user, who controls all instances. Who would decide to perform a MITM attack in his own network?</div></div><div class="gmail_extra"><br><div class="gmail_quote">2018-03-19 12:53 GMT+03:00 Kevin Benton <span dir="ltr"><<a href="mailto:kevin@benton.pub" target="_blank">kevin@benton.pub</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto">Do you need to spoof arbitrary addresses? If not (i.e. a set you know ahead of time), you can put entries in the allowed_address_pairs field of the port that will allow you to send traffic using other MAC/IPs.</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Mar 19, 2018 8:42 PM, "Vadim Ponomarev" <<a href="mailto:ponomarev@selectel.ru" target="_blank">ponomarev@selectel.ru</a>> wrote:<br type="attribution"><blockquote class="m_-4251210864703811718quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi,<div><br>I support, that is a problem. It's unclear, how after removing the option prevent_arp_spoofing, I can manage the prevent ARP spoofing mechanism. Example: I use security groups but I don't want to use ARP spoofing protection. How do I can disable the protection?<br></div></div><div class="gmail_extra"><div class="m_-4251210864703811718elided-text"><br><div class="gmail_quote">2018-03-14 10:26 GMT+03:00 Tatiana Kholkina <span dir="ltr"><<a href="mailto:holkina@selectel.ru" rel="noreferrer" target="_blank">holkina@selectel.ru</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Sure, there is an ability to enable ARP spoofing for the port/network, but it is impossible to make it enabled by default for all ports.<div>It looks a bit complicated to me and I think it would be better to have an ability to set default port security via config file.</div><div><br></div><div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Best regards,</span></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Tatiana</span></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">2018-03-13 15:10 GMT+03:00 Claudiu Belu <span dir="ltr"><<a href="mailto:cbelu@cloudbasesolutions.com" rel="noreferrer" target="_blank">cbelu@cloudbasesolutions.com</a>></span><wbr>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">Hi,<br>
<br>
Indeed ARP spoofing is prevented by default, but AFAIK, if you want it enabled for a port / network, you can simply disable the security groups on that neutron network / port.<br>
<br>
Best regards,<br>
<br>
Claudiu Belu<br>
<br>
<div style="font-family:Times New Roman;color:#000000;font-size:16px">
<hr>
<div id="m_-4251210864703811718m_1915042392102507057m_6589341003032362246m_-9048447337040272059divRpF369882" style="direction:ltr"><font size="2" face="Tahoma" color="#000000"><b>From:</b> Татьяна Холкина [<a href="mailto:holkina@selectel.ru" rel="noreferrer" target="_blank">holkina@selectel.ru</a>]<br>
<b>Sent:</b> Tuesday, March 13, 2018 12:54 PM<br>
<b>To:</b> <a href="mailto:openstack-dev@lists.openstack.org" rel="noreferrer" target="_blank">openstack-dev@lists.openstack.<wbr>org</a><br>
<b>Subject:</b> [openstack-dev] [neutron] Prevent ARP spoofing<br>
</font><br>
</div><div><div class="m_-4251210864703811718m_1915042392102507057m_6589341003032362246h5">
<div></div>
<div>
<div dir="ltr">Hi,
<div>I'm using an ocata release of OpenStack where the option prevent_arp_spoofing can be managed via conf. But later in pike it was removed and it was decided to prevent spoofing by default.<br>
</div>
<div>There are cases where security features should be disabled. As I can see now we can use a port_security option for these cases. But this option should be set for a particular port or network on create. The default value is set to True [1] and it<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline">t
is impossible to change it</span>. I'd like to suggest to get default value for port_security [2] from config option.</div>
<div>It would be nice to know your opinion.<br>
</div>
<div><br>
</div>
<div>[1] <a href="https://github.com/openstack/neutron-lib/blob/stable/queens/neutron_lib/api/definitions/port_security.py#L21" rel="noreferrer" target="_blank">https://github.com/<wbr>openstack/neutron-lib/blob/<wbr>stable/queens/neutron_lib/api/<wbr>definitions/port_security.py#<wbr>L21</a></div>
<div>[2] <span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline"><a href="https://github.com/openstack/neutron/blob/stable/queens/neutron/objects/extensions/port_security.py#L24" rel="noreferrer" target="_blank">https://github.com/<wbr>openstack/neutron/blob/stable/<wbr>queens/neutron/objects/<wbr>extensions/port_security.py#<wbr>L24</a></span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline"><br>
</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline">Best
regards,</span></div>
<div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);float:none;display:inline">Tatiana</span></div>
</div>
</div>
</div></div></div>
</div>
</div>
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<br></blockquote></div><br><br clear="all"><div><br></div></div><div class="m_-4251210864703811718signature-text">-- <br><div class="m_-4251210864703811718m_1915042392102507057gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><font face="tahoma, sans-serif" color="#999999"><span style="font-size:12.8px">Best regards,</span><br>Vadim Ponomarev<br>Developer of network automation department at Selectel Ltd.<br><br><span style="font-size:12.8px">----</span><br><span style="font-size:12.8px">This message may contain confidential information that can't be distributed without the consent of the sender or the authorized person </span><span style="font-size:12.8px">Selectel Ltd</span><span style="font-size:12.8px">.</span></font></div></div></div></div></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><font face="tahoma, sans-serif" color="#999999"><span style="font-size:12.8px">Best regards,</span><br>Vadim Ponomarev<br>Developer of network automation department at Selectel Ltd.<br><br><span style="font-size:12.8px">----</span><br><span style="font-size:12.8px">This message may contain confidential information that can't be distributed without the consent of the sender or the authorized person </span><span style="font-size:12.8px">Selectel Ltd</span><span style="font-size:12.8px">.</span></font></div></div></div></div></div>
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