SIP NAT on Cisco IOS stop working

Suddenly you realized that external SIP phones stop working without any reason, you should be avare of Cisco routers get stuck sometimes. There is a trick to solve the issue with two commands, but first of all be sure that the sip is not registered through arterisk cli: Type on your asterisk: asterisk -rvvvvv and […]

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Cisco Router IPv6 Configuration

In the beginning of the year 2011, we decided to apply IPv6 configuration to our data center (VeriTeknik) and requested our IPv6 block from RIPE. RIRs give out /32 blocks to LIRs at the first assignment. The Preperation Steps Request your IPv6 Addresses from your RIR or LIR Add IPv6 Route to your AS number […]

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Cisco PIX & ASA Host name in greeting fix

If it appears to be all (***) instead of your mail hostname and if you get, “550 Sorry, your HELO/EHLO greeting must resolve (#5.7.1)” error when sending mail to your mail server from outside, run the following command in your CISCO firewall: no fixup protocol smtp 25 and save with the “wr mem” command Related […]

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