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Is any special configuration needed to use a dynamic IP address?

April 26, 2017address configuration dynamic ip needed special

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Is any special configuration needed to use a dynamic IP address?

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Yes. In order to avoid giving indigestion to certain picky MTAs (notably exim), fetchmail always makes the RCPT TO address it feeds the MTA a fully qualified one with a hostname part. Normally it does this by appending @ and “localhost”, but when you are using Kerberos or ETRN mode it will append @ and your machine’s fully-qualified domain name (FQDN). Appending the FQDN can create problems when fetchmail is running in daemon mode and outlasts the dynamic IP address assignment your client machine had when it started up. Since the new IP address (looked up at RCPT TO interpretation time) doesn’t match the original, the most benign possible result is that your MTA thinks it’s seeing a relaying attempt and refuses. More frequently, fetchmail will try to connect to a nonexistent host address and time out. Worst case, you could up forwarding your mail to the wrong machine! Use the smtpaddress option to force the appended hostname to one with a (fixed) IP address of 127.0.0.1 in your /etc/ho

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No. Fetchmail itself doesn’t care whether the IP address you use is static (fixed) or dynamic (varying, allocated at connection time by your ISP from an address pool). In fact, fetchmail normally doesn’t use your address explicitly at all; it only cares that you have a working gateway.